govoplan-mail/docs/MAIL_HANDBOOK.md

Mail Handbook

Purpose and status

This handbook is the canonical multi-perspective description of the GovOPlaN Mail module. Mail is a governed transport and mailbox capability. It is not a campaign definition, contact database, or general records store.

Perspective	Start here
User selecting a profile or reading a mailbox	User tasks
Mail profile administrator	Profile administration
Policy or tenant administrator	Policy hierarchy
Delivery operator	Operations and recovery
Integrator	Capability contract
Security or audit reviewer	Security, deletion, and audit
Release reviewer	Acceptance checklist

See also Mail protocol roadmap and the Campaign Mail profile boundary.

Domain ownership

Mail owns:

• reusable SMTP/IMAP/JMAP profile definitions, dedicated legacy POP3 sources, and scope;
• encrypted SMTP/IMAP/JMAP/POP3 credentials and safe credential replacement;
• effective profile policy and visibility/authorization decisions;
• connection tests and protocol adapters;
• SMTP send and IMAP append operations exposed to consumers;
• read-only IMAP/JMAP mailbox folder/message access, bounded indexes, and encrypted pending-review records imported from legacy POP3 sources; and
• the transport sanitization boundary and throttling behavior. A general Mail-owned provider-attempt/diagnostic ledger remains planned.

Consumers own their business intent. For example, Campaign owns message content, recipients, approval, jobs, and delivery evidence, while Mail owns the profile and performs the provider operation. A consumer stores only a stable Mail profile reference and non-secret evidence returned by Mail. It never receives decrypted credentials or a raw resolved transport configuration.

Core owns authentication, tenant context, permission evaluation, database session primitives, cryptographic secret helpers, audit infrastructure, and the module registry. Optional consumers provide narrow context through capabilities; Mail does not import their ORM or service implementations.

Deployment configuration packages

Mail registers the mail.configuration capability for smtp_profile fragments. The provider reads the validated mail.smtp entry from the installer-generated infrastructure capability receipt. Receipt host and port are authoritative; the generic package workflow asks for missing non-secret transport fields such as security mode. An external relay may operate without authentication, or the operator may select an existing credential-envelope id. Inline usernames, passwords, tokens, and secret values are rejected.

Tenant scope is the default. A system-scoped profile requires system settings or governance write authority. The fragment's stable slug is its idempotency identity: an absent profile is created, an exact profile is skipped, and a conflicting profile is preserved unless the reviewed fragment explicitly sets on_conflict to update. Credential bindings are added idempotently and are never removed merely because a package omits a credential reference.

Mail also registers a module-owned infrastructure dependency provider. Its authorized Ops inventory lists every persisted SMTP endpoint and legacy SMTP profile by stable non-secret reference, state and scope, together with numeric credential-binding evidence. Before the host deployer changes or removes mail.smtp, it requires a fresh, complete inventory from the same installation and displays these dependencies in the plan. The inventory never contains transport credentials or decrypted envelope data.

Preflight does not prove SMTP reachability. After apply, use the normal Mail profile test and Ops health surfaces. If the receipt says SMTP is unavailable, is invalid, or is not mounted, import is blocked with an operator-facing resolution instead of creating a partial profile.

Configuration packages remain SMTP-focused. A POP3 legacy source is a deliberate operational migration action and is not silently exported, cloned, or enabled by an SMTP profile package.

Interface patterns and unavailable actions

Mail uses the platform's shared explorer, connection tree, adaptive form, effective-policy, dialog, status, alert, and confirmation components. The module-owned surface inventory and consequence classification are recorded in Mail interface pattern migration.

An unavailable action remains visible when it belongs to the current task. Its hover/focus explanation identifies the missing field, active operation, or permission. Larger blockers state what must change, who can change it, and where to go. Contextual Help Center links resolve to the configured Docs module when installed and otherwise use the public documentation fallback.

Mailbox reads, profile reloads, connection tests, policy saves, bounce scans, and destructive actions each expose their current loading or blocked state. Removing a bounce watcher and deactivating profile hierarchy items use shared confirmation dialogs. Removing a watcher retains existing observations; deactivating a profile may scrub Mail-owned credentials as described below.

Concepts

Profile

A profile is a reusable, named delivery identity with optional SMTP and IMAP configuration and one or more opt-in JMAP mailbox endpoints. It can additionally own a dedicated POP3 endpoint for an explicit legacy-import workflow. It has a stable id, lifecycle state, scope, owner context, and non-secret connection metadata. Passwords are write-only encrypted values and are never returned through list/read/capability responses.

An IMAP server may map the standard Inbox, Sent, Drafts, Trash, Archive, and Junk roles to exact provider folder names. These mappings belong to the reusable profile/server. Empty roles retain automatic behavior. The historical imap.sent_folder value is read as the Sent mapping and remains synchronized for compatibility; a Campaign-specific Sent override still wins for that Campaign.

Use readable Unicode names such as Entwürfe, not IMAP wire encodings such as Entw&APw-rfe. Discovery decodes modified UTF-7 before detecting standard folder roles; SELECT, STATUS, and Sent APPEND encode and quote the chosen name for the active connection. Literal ampersands, quotes, backslashes, and Unicode characters round-trip without renaming remote folders. Previously saved wire-form names are resolved against that account's live folder list; if the same string is also an actual readable folder name, the readable name wins. Rediscovery and an explicit profile save replace old encoded configuration values with readable names; background reads never rewrite configuration.

Profiles may be scoped to system, tenant, user, group, or campaign context. Scope controls where a profile can be discovered; effective policy can narrow that further. A visible profile is not automatically authorized for every operation: using, testing, managing, and managing secrets are separate rights.

Policy

Mail policy controls approved profile ids, which lower scopes may define profiles, allowed/denied SMTP/IMAP/JMAP hosts and addressing patterns, credential inheritance, and lower-level limits. The effective result is assembled from applicable system, tenant, user/group, and campaign context. Denials and locked parent limits cannot be relaxed by a lower scope.

Transport identity and revision

Mail owns opaque random revisions for relevant SMTP/IMAP/JMAP identity and configuration. They are concurrency tokens, not deterministic hashes that a consumer could use to guess a host or account. Credentials are excluded. A consumer can freeze these revisions at build time and ask Mail to require the same identity when the effect is later performed. Credential rotation alone therefore need not invalidate prepared work, while a host/account/protocol identity change does.

The revision is evidence and a concurrency guard, not a substitute for authorization. Mail re-evaluates profile activity, visibility, policy, and revision immediately before it resolves credentials and performs the effect.

POP3 imports pin the endpoint/credential transport revision at preview time. A changed revision or a missing provider UIDL stops import and requires a fresh preview. POP3 does not participate in the ordinary mailbox folder/message projection.

Provider outcomes

SMTP acceptance, partial or complete recipient refusal, temporary/permanent failure, connection loss, and unknown outcome are distinct. IMAP append is a separate operation and outcome. Ordinary Campaign recipient delivery retains its Campaign-owned job ledger. Mail owns an encrypted durable command and attempt ledger for report delivery and other effects that do not have such a consumer ledger.

The Mail worker commits an attempt before it starts SMTP and then commits an effect-start marker before opening the provider effect. Worker redelivery may recover a stale pre-effect claim, but an accepted, partially accepted, in-progress-after-effect, or unknown command is never sent automatically. Unknown outcomes require a separately authorized reconciliation with an external evidence reference. A deliberate resend creates a new command with a new idempotency key and links it to the prior command.

User tasks

Choose a profile

1. Open the task that requires mail, such as Campaign Mail settings.
2. Choose from the profiles visible and authorized for the current tenant, owner, group, and task context. Never enter or copy a profile id manually when the UI can present a picker.
3. Review the safe summary: name, scope, active state, SMTP/IMAP/JMAP availability, and policy-relevant sender identity. Credentials and raw provider internals are not visible.
4. Save the reference in the consuming module. If ownership or policy changes, select and validate again.

The user needs mail:profile:use; reading profile summaries and testing may require their own scopes. The consuming module still requires its own action permission.

Test a profile

An authorized profile test verifies connection and authentication for the selected active/visible SMTP, IMAP, or JMAP profile using Mail-owned credentials. The consumer-use path evaluates effective Mail policy separately. Use a non-production provider and mailbox first. A successful connection test does not prove policy authorization for a later Campaign context, deliverability, recipient acceptance, SPF/DKIM/DMARC alignment, or future availability.

Campaign runtime authorization follows the protocol being used: SMTP batch and single-message calls enforce the explicit SMTP credential policy, while append-to-Sent enforces the IMAP credential policy. A valid SMTP call does not need to carry an unrelated IMAP credential just because the profile supports both protocols. Full campaign authoring validation and complete profile summaries continue to require both configured selections when their policies forbid inherited credentials. The selected protocol's missing credential, inactive/unauthorized binding or stale transport revision still stops the operation before decryption or provider contact. Resolving a policy rejection never requires disabling TLS or weakening either credential policy. Correcting this runtime check does not change stored configuration or approved builds, reset job state, or retry/send messages automatically.

Testing a saved profile requires both mail:profile:test and mail:profile:use, and the profile must be active. Profile creation or test authority alone is not enough.

Raw settings test endpoints accept new settings only for actors who may both test profiles and manage secrets. They are an administration aid, not a way for ordinary consumers to bypass reusable profiles.

Read a mailbox

The persistent workspace header contains the profile selector, Mailbox tools, Help, and one right-aligned Reload. These controls remain available when the mailbox is empty or no usable profile is configured. Reload rechecks the permitted profiles and refreshes the current folder catalogue and bounded message page; it also rereads a selected message if that message remains on the page. IMAP keeps the page offset. JMAP starts a fresh cursor chain at page one while keeping the search term. An unavailable profile is replaced only by another currently authorized active profile, or the explicit no-profile state.

Folder icons expand or collapse; labels select. Synthetic grouping labels select the group without reading a nonexistent provider folder, and Reload in that state refreshes only the folder catalogue. Refreshes keep user-controlled expansion. A failed refresh preserves usable loaded data, shows the error, and leaves Reload available for retry; late responses from an earlier profile or tenant cannot replace the current context. Mailbox context reads bypass browser response/promise reuse so an immediate Reload really rechecks permissions and state. Mail's bounded server-side index is unchanged; its explicit refresh flag and live/cached provenance still apply. Failed pagination restores the page and page-size labels belonging to retained rows. Dismissing or changing the preview while Reload is pending takes precedence over its remembered selection. On narrow screens, scroll vertically through folders, message list, and preview within the mailbox workspace; the profile/tools/Reload header remains visible.

Mailbox tools groups the occasional profile-only, folder-only, and message-only refreshes in a dialog, separate from Bounce status. Bounce status requires mail:bounce:read or mail:bounce:manage; without either it remains visible and disabled with an explanation. Escape closes this dialog without clearing the selected message. These read controls do not grant profile administration, send SMTP messages, APPEND messages, or change mailbox flags.

The current mailbox UI and API are read-only. An authorized user can list IMAP or JMAP folders, page through messages, and inspect a bounded full message. IMAP folder names are decoded for display and encoded and quoted defensively for mailbox commands; Sent-folder discovery uses provider flags and common readable names. The default IMAP4rev1 mode uses modified UTF-7. A connection that has explicitly enabled UTF8=ACCEPT uses UTF-8 instead; merely advertising that capability does not change encoding. Invalid provider encodings produce an explicit error rather than a replacement name that could address another folder. Refresh any already-loaded folder list after upgrading. JMAP discovers the Session and Mail account, uses Mailbox/get hierarchy and roles, runs text search with Email/query, and uses Email/get for bounded summaries/details. Email/changes exposes a bounded incremental cursor; an expired state tells the caller to perform a full refresh. The list exposes the provider's Seen/$seen state as a read/unread indicator without changing it. It also labels whether the current page came directly from the provider, from the bounded mailbox index, or from an index while a refresh is in progress, including the index timestamp when available.

The mailbox-name boundary follows RFC 3501 section 5.1.3 and, only after explicit activation, RFC 6855 section 3.

Message HTML is displayed only in the shared sandboxed message component. Remote URLs and active markup are removed, embedded data:/cid: image references remain isolated, and plain text is always available when supplied. Attachments and provider/content failures remain explicit rather than being silently interpreted as an empty message.

Mailbox access requires both mail:mailbox:read and mail:profile:use. It must not mutate read/unread, delete, move, or reply state. Message responses are bounded by the endpoint response/body policy; ordinary UI should avoid loading a whole large mailbox or attachment merely to show a list.

JMAP is opt-in per server endpoint. Its authenticated Session URL is governed by jmap_hosts; an advertised API URL on another origin fails closed unless that origin is explicitly listed for the endpoint. Bearer tokens or Basic credentials are stored only in Mail credential envelopes. This slice does not send through JMAP, mutate provider state, download attachment binaries, or add calendar/contact/thread features.

Import a legacy POP3 mailbox

POP3 is available only for bounded migration from a legacy server that cannot provide IMAP or JMAP. It is disabled by default and is not a replacement for the read-only mailbox UI.

1. An actor with profile-write, secret-management, and mail:pop3:manage authority opens Legacy POP3 import, selects a Mail profile, and creates a dedicated source. The UI stages the endpoint disabled, stores its encrypted username/password credential, and enables it only after both operations succeed.
2. The administrator explicitly enables legacy import, sets TLS mode, timeout, maximum message and batch sizes, and preview body lines, and tests connection, authentication, TLS, and provider message count. Plain transport remains subject to deployment egress/security policy and should not be used across an untrusted network.
3. An operator with mail:profile:use and mail:pop3:import refreshes a live preview of at most 100 messages. Preview sends no DELE, changes no flags, and exposes only bounded headers/body text. A server without stable UIDL identifiers is rejected. If TOP is unavailable, Mail uses RETR only inside the configured size bound and suppresses an oversized preview.
4. The operator selects messages. Mail downloads within the size gate and creates encrypted local pending_review records. Tenant, profile, endpoint, and UIDL form the duplicate boundary. Raw content never appears in list, provider-state, audit, or DSAR output.
5. Source messages remain untouched by default. Delete-after-import requires the endpoint's separate allow_delete_after_import policy, the operator's mail:pop3:delete permission, an explicit per-batch choice, and destructive confirmation. Mail commits the local import plus mail.pop3.imported audit evidence before sending DELE. It separately records mail.pop3.source_deletion; disconnect during QUIT is outcome-unknown and must be reconciled before another destructive attempt.

The supplied Mail legacy import operator role can test, preview, and import without deleting. The Mail profile administrator role also contains source management and destructive-delete permissions; deployments should remove or split mail:pop3:delete when operators must never delete provider messages. Imported records follow configured Mail/records retention and require manual review for a data-subject request or deletion decision.

Contextual help is available from the page and from each policy-sensitive source setting, credential field, size limit, import action, and destructive confirmation. Press F1 while a control has focus to open the Mail-owned German reference for the exact POP3 context; the same topic remains available through the page help action.

Profile administration

Roles

The supplied templates are:

• Mail profile user: read/use/test approved profiles and read permitted mailboxes without reading secrets.
• Mail profile self-service user: additionally create, edit, deactivate, and manage credentials only for the current account's own user-scoped profiles, subject to the effective Mail policy.
• Mail profile administrator: additionally create/update profiles and create/replace encrypted credentials across tenant-owned scopes, configure legacy POP3 imports, and—unless the template is narrowed—request source deletion after import.
• Mail legacy import operator: test approved POP3 sources and preview/import messages without permission to delete them at the provider.

The specific permissions are mail:profile:read, mail:profile:use, mail:profile:test, mail:mailbox:read, mail:profile:write_own, mail:secret:manage_own, mail:profile:write, mail:secret:manage, mail:pop3:manage, mail:pop3:import, and mail:pop3:delete. The _own permissions are enforced against the authenticated membership id and never authorize a tenant, group, campaign, system, or another user's profile. They also do not authorize profile-policy changes. System-scoped definitions use the corresponding system settings authority. Keep secret management separate when an institution wants profile metadata administrators not to know or replace credentials.

That separation is fail-closed for transport rebinding: changing an SMTP or IMAP host, port, or security mode while the profile retains a stored password requires the matching secret-management permission. A credential-free profile can be deactivated with profile-write authority alone; deactivation that scrubs a stored password also requires secret-management authority and records the deletion in the audit log.

Create or change a profile

The configured Help Center exposes Create a custom Mail profile only when the current actor has broad or self-service profile-write authority and the effective user-scope policy permits user profiles. It states the active SMTP/IMAP/JMAP hostname allow-list groups and deny rules, plus the actor's separate credential, test, use, and approval requirements. The Settings task creates in the current account's user scope. Grant mail:profile:write_own for self-service; mail:profile:write remains broad profile administration authority.

1. Choose the narrowest suitable scope and a stable, descriptive name/slug.
2. Configure SMTP and optional IMAP, or add an optional JMAP Session endpoint after creating the profile. Set TLS mode, account identity, standard folder mappings, and timeouts. Folder discovery proposes provider-visible Inbox, Sent, Drafts, Trash, Archive, and Junk names without mutating the mailbox. Sender/envelope/recipient constraints belong to effective Mail policy; Campaign rate limits remain delivery configuration.
3. Enter credentials only in the dedicated credential fields. Returned profile data indicates whether credentials are configured without returning them.
4. Save and run SMTP/IMAP/JMAP tests against a non-production target.
5. Verify the effective policy for every intended consumer context.
6. Communicate changes that alter the non-secret transport identity; prepared consumer snapshots will deliberately stop until rebuilt.

An update that omits a password preserves the current encrypted password. A credential replacement never depends on reading the old cleartext value back.

The shared credential editor resolves Mail server restrictions from the authorized metadata catalogue when it opens. Names appear as loading completes; no page refresh is required, and typing in a draft does not reload the catalogue. Closing and reopening refreshes the available servers and can retry a temporary metadata failure. Inactive servers remain labelled inactive; deleted or unauthorized references remain visible as unavailable and are never silently removed from the credential. Labels do not grant permission to use a server, and the lookup does not retrieve secrets. If saving a reusable credential fails, the editor shows the error beside the unchanged draft. Retry explicitly after correcting the cause. Saving disables editing and closing until the request finishes; a failed save never silently discards a replacement secret that has not been stored.

Delete a profile

Profile deletion is immediate for Mail-owned secrets and audit evidence:

1. Mail clears encrypted SMTP, IMAP, JMAP, and POP3 credential envelopes in the same transaction.
2. It deactivates the remaining non-secret tombstone state so historical stable references can fail safely rather than resolve to another profile.
3. When owned encrypted secrets existed, it emits mail.profile_credentials_deleted with profile id, scope, reason, and the kinds of secret removed—never values, usernames/passwords, or raw configuration.
4. If scrubbing or audit insertion fails, the transaction rolls back and the deletion fails.
5. Repeating deletion after the secrets are gone is an idempotent no-op for the secret-deletion effect.

Consumers that still reference the profile fail closed at validation or execution. Deletion does not silently rebind them to a default profile.

Policy hierarchy

Effective policy is contextual. Administrators should document:

• which profile ids are approved globally or for a tenant;
• whether tenant, user, group, or campaign-scoped profiles may be created;
• allowed and denied SMTP/IMAP/JMAP hosts;
• permitted From, envelope sender (including bounce address), and envelope recipient-domain patterns;
• whether SMTP/IMAP may use a default credential or require an explicit Mail-owned credential selection; and
• which lower-level settings are locked by a parent policy.

In Mail profile policy → Credential selection, SMTP and IMAP have separate controls. Allow profile default credential (inherit: true) permits either the selected server's default credential or an explicit authorized Mail-owned credential. Require explicit Mail credential (inherit: false) requires a server and credential reference in Campaign Mail settings. Neither option permits campaign-local passwords or copies a secret into Campaign.

Inherit policy from parent leaves the local value unset; it is different from allowing a server's default credential. System policy always has a concrete choice. Other scopes show the local choice alongside the saved effective result and policy path. Allow override controls allow_lower_level_limits["smtp_credentials.inherit"] and the equivalent IMAP key. It is not a separate allow_override field in the credential object. A parent's explicit-credential requirement may be changed by a child only while that parent allows overrides. Locked fields and their override controls remain read-only; a lower scope cannot unlock them. Campaign policy has no lower-level override controls. Editing any policy still requires that scope's policy-write permission and an unlocked workflow.

Policy saves retain their draft after a failed write and require an explicit retry. If the policy was saved but a dependent screen refresh fails, the editor reports that the policy was saved and advises reloading the display; it does not report a failed save or repeat the accepted write.

Policy reads are available through system/tenant/context routes to suitably authorized actors. Adaptive Docs exposes a safe explanation of the effective tenant posture; it does not expose credential material.

Operations and recovery

Deployment egress policy

Private-network connector access is controlled deployment-wide by GOVOPLAN_CONNECTOR_ALLOW_PRIVATE_NETWORKS. Whether private or public targets are allowed, SMTP, IMAP, and legacy POP3 resolve, validate, and connect to the exact approved address records at connection time while retaining the original hostname for TLS SNI and certificate verification. A DNS change cannot redirect the socket after validation.

Transports that cannot pin every connection peer or revalidate protocol-managed redirects/referrals must fail before client construction. Do not weaken this rule to make a target test pass; change the connector implementation or the target topology.

Response and time bounds

The shared defaults are 16 MiB for structured connector responses and 512 MiB for file transfers. Mailbox full-message fetch additionally uses bounded IMAP ranges and the applicable deployment limit. Operators may lower limits for their environment. A declared or streamed over-limit response fails visibly rather than being retained partially as if complete.

Configure connection/read timeouts and provider-specific message/attachment limits. A timeout after the SMTP effect may be an unknown outcome; it must not be flattened into a safe-to-retry connection failure.

Throttling

Mail rate limiting uses a Redis lock and next-allowed timestamp across worker processes when worker mode is enabled. Direct development uses a process-local limiter. If Redis fails in worker mode, the current implementation silently falls back to a limiter that protects only that process; it does not provide cluster-wide coordination or emit its own health signal. Production operators must therefore monitor Redis independently and should stop or restrict multi-worker delivery during an outage until explicit degradation telemetry is implemented.

SMTP/IMAP incidents

Current SMTP delivery and Sent-folder APPEND paths start a Mail-owned Core recovery operation before the network effect. Outbox attempts use the durable command and attempt number; Campaign jobs and single-message actions pass their own stable attempt identifiers through the versioned capability. A matching completed identifier is never sent or appended again merely to reconstruct caller state. Provider acceptance, definitive rejection, and outcome-unknown states are recorded independently of the consuming transaction.

Mailbox folder/message indexing and configured bounce/calendar-reply scans are read-only provider operations. They acquire distributed per-profile/folder or per-source fences, commit bounded projection state, and verify that state in an independent session. A failed read is rolled back and can be repeated; it is not treated as an unknown provider mutation.

1. Stop new consumer work if duplicate effects or credential compromise are possible.
2. Preserve safe Mail, consumer-job, worker, and provider evidence.
3. Rotate credentials in Mail. Rebuild consumers only if the revisioned non-secret identity also changed.
4. Treat post-command connection loss as potentially unknown until provider evidence establishes whether SMTP accepted the message.
5. Handle IMAP append failure independently; do not resend an accepted message merely to recreate a Sent copy.
6. Record the incident/reconciliation reference in the consuming domain's audit trail without copying raw provider secrets or message content unnecessarily.
7. For an outbox outcome_unknown, reconcile the Mail command with provider evidence. Confirmed acceptance closes the provider operation as succeeded; confirmed absence records verified recovery and permits only a new, deliberate attempt identifier.

Bounded IMAP append batches / Begrenzte IMAP-Ablagestapel

Campaign's bulk Sent-folder operation can use the optional mail.campaign_delivery.campaign_imap_batch(tenant_id=..., campaign_id=...) context. Opening this context has no provider effect. Mail opens a connection only after an individual message passes its current authorization, selected IMAP credential policy, both frozen transport revisions and durable recovery checks. Subsequent messages reuse that authenticated connection and its detected Sent folder, including the provider's original Unicode mailbox wire encoding. Authorization and credential resolution are performed for every message, not cached. Changing the authorized profile, selected references, folder or resolved credentials releases the previous connection before the next APPEND.

Each message still receives one sequential APPEND and its own recovery evidence. There is no parallel APPEND, MULTIAPPEND, automatic SMTP resend or replay after APPEND starts. A lost APPEND reply remains outcome-unknown and requires explicit mailbox reconciliation. Failures while connecting, before any APPEND, may use a bounded reconnect; rejected authentication is not retried. A failure to finalize accepted recovery evidence closes the batch. Cleanup/logout failure does not turn an accepted APPEND into a failed one. Session state is scoped to the current batch, never shared across tenants or campaigns, and is released on exit.

Deployment controls apply to batch connection reuse, not campaign authorization:

Environment variable	Default	Range / effect
GOVOPLAN_IMAP_BATCH_REUSE	true	false, 0, no or off disables reuse.
GOVOPLAN_IMAP_BATCH_MAX_MESSAGES	100	1–10,000 successful APPENDs per connection.
GOVOPLAN_IMAP_BATCH_MAX_AGE_SECONDS	300	1–3,600 seconds; rotate before the next message, not during an APPEND.
GOVOPLAN_IMAP_BATCH_IDLE_HEALTH_CHECK_SECONDS	30	0–3,600 seconds idle before a NOOP; 0 checks every reuse.
GOVOPLAN_IMAP_BATCH_RECONNECT_ATTEMPTS	1	0–5 extra connection attempts, only before APPEND.

Invalid numeric values use defaults; out-of-range numbers are clamped. An active session keeps the policy with which it was created. Existing single-message callers retain one connection per call and no automatic connection retries. Older Mail capabilities without this optional context keep the single-message behavior. Safe outcome fields include connection sequence, session reuse and reconnect count; they contain no hosts, credentials, provider responses or MIME content. Fewer logins and folder discoveries improve connection overhead, not the provider's intrinsic per-message APPEND or durable-evidence latency.

Deutsch: Die Sammelablage im Gesendet-Ordner kann eine begrenzte authentifizierte IMAP-Verbindung wiederverwenden. Der Stapelkontext allein verbindet sich nicht. Vor jeder Nachricht prüft Mail erneut Berechtigung, IMAP-Zugangsdatenrichtlinie, beide eingefrorenen Transportrevisionen und Wiederherstellungsnachweise; die Zugangsdaten werden weiterhin je Nachricht aufgelöst. Profil, ausgewählte Referenzen, Ordner oder aufgelöste Zugangsdaten dürfen nicht stillschweigend von einer älteren Verbindung übernommen werden. Ordnererkennung und ursprüngliche Provider-Kodierung bleiben ausschließlich an dieselbe Verbindung gebunden.

Jede Nachricht erhält weiterhin einen einzelnen, sequenziellen APPEND und einen eigenen Nachweis. Es gibt kein paralleles APPEND, kein MULTIAPPEND und keine automatische Wiederholung nach Beginn von APPEND. Ein unbekanntes Ergebnis muss am Postfach abgeglichen werden; eine fehlende Gesendet-Kopie darf keinen erneuten SMTP-Versand auslösen. Nur Verbindungsaufbau vor APPEND darf begrenzt wiederholt werden, nicht eine abgelehnte Anmeldung. Ein Fehler beim Abschluss des Wiederherstellungsnachweises schließt den Stapel; ein reiner Abmeldefehler macht eine bestätigte Ablage nicht rückgängig. Mandanten und Kampagnen teilen keine Stapelverbindung.

Die obigen Betriebsvariablen bedeuten standardmäßig: Wiederverwendung aktiv, höchstens 100 Nachrichten bzw. 300 Sekunden pro Verbindung, NOOP nach 30 Sekunden Leerlauf und höchstens einen zusätzlichen Verbindungsversuch vor APPEND. Der Wechsel erfolgt vor der nächsten Nachricht, niemals mitten im APPEND. 0 beim Leerlaufintervall prüft jede Wiederverwendung; deaktivierte Wiederverwendung verwendet weiterhin einzelne APPENDs. Ungültige Zahlen verwenden den Standard, Zahlen außerhalb des Wertebereichs werden begrenzt. Eine aktive Verbindung behält ihre beim Aufbau gelesene Richtlinie. Einzelaufrufe und ältere optionale Mail-Verträge bleiben kompatibel. Verbindungszähler enthalten keine Zugangsdaten oder Providerdetails. Die Optimierung spart Verbindungsaufbau und Ordnersuche; Provider-Ablage und dauerhafte Einzelnachweise benötigen weiterhin ihre Zeit.

Delivery-status and calendar-reply sources

An authorized Mail bounce source scans a bounded IMAP UID range without changing mailbox flags. It correlates DSN reports with durable Mail commands and, when the optional Calendar invitation capability is active, forwards text/calendar or .ics METHOD:REPLY parts to Calendar. Calendar remains owner of attendee state; Mail records only a raw digest, mailbox coordinates, Message-ID, and audit linkage. Ordinary or malformed calendar messages do not block DSN progress. A repeated UID/message digest produces no second Calendar state transition or outbound synchronization effect.

Backup, restore, and retirement

Backups contain encrypted credentials and encrypted raw POP3 import records and therefore need the same protection as the live database and key material. Restoring a Mail database without the matching encryption key makes those records unusable; restoring it with keys can reactivate sensitive historical state and must be controlled.

Destructive module retirement first applies the same immediate credential scrub/audit rule to every remaining profile, then drops Mail-owned tables after the installer snapshot/confirmation gate. Any scrub or audit failure blocks retirement. Historical backups are separate retained copies and require the deployment's approved backup-destruction policy.

Capability contract

Mail provides mail.campaign_delivery version 0.2.x. This version is a breaking ownership boundary: it exposes reference-oriented operations, not raw resolved configuration or credentials.

The Mail REST API supplies the profile list used by pickers. Given a stable profile reference, the capability supports these kinds of operation:

• resolve a profile reference and evaluate its Mail context/policy to produce a non-secret delivery summary and opaque Mail-owned revisions;
• send Campaign-owned RFC message bytes using the selected profile;
• optionally append an accepted message to Sent; and
• return sanitized outcome/revision evidence.

For a real effect, one Mail call must:

1. resolve current campaign/tenant/owner context through the optional narrow context capability;
2. load the selected active profile;
3. evaluate profile-scope eligibility and effective policy;
4. compare the consumer's expected opaque transport revision;
5. decrypt credentials in Mail memory;
6. perform the SMTP or IMAP operation; and
7. return only the safe result.

Keeping comparison, credential resolution, and transport inside one operation avoids a time-of-check/time-of-use gap and prevents the consumer from becoming a credential-processing boundary. The capability does not receive the acting principal: the Campaign route must first enforce mail:profile:use, while Mail still re-evaluates active profile scope and contextual policy inside the call.

Mail optionally consumes campaigns.mail_policy_context and addresses.lookup. Their physical absence must leave Mail installable and its unrelated profile/mailbox behavior usable. Interface-version compatibility is a mandatory release gate.

Security, deletion, and audit

Security invariants:

• Decrypted SMTP/IMAP passwords and JMAP/POP3 credentials never cross the Mail capability/API boundary.
• Password fields are write-only and encrypted at rest; safe responses expose configuration state, not values.
• Consumers persist stable profile references, not transport copies.
• Host policy is deployment-wide and every supported connection is DNS/IP pinned at socket creation.
• Redirect/referral-capable transports fail closed unless every peer can be revalidated and pinned.
• Profile deletion and destructive retirement scrub every Mail-owned encrypted password and emit non-secret audit in the same lifecycle action.
• Mailbox reads are separately authorized, read-only, paginated, and bounded.
• Logs/audit/results minimize message content, addresses, provider responses, and secret-like values.

Credential replacement/deletion emits canonical non-secret Mail audit events. Profile/policy create/update/deactivate currently emits change-feed evidence, but connection tests and the complete administrative lifecycle do not yet have equivalent canonical audit events. Mail delivery commands emit request, terminal-outcome, reconciliation, and deliberate-resend events without addresses or raw provider responses. MIME, envelope addresses, detailed refusals, and reconciliation notes are encrypted and minimized after their retention deadline while hashes, counts, attempts, and decisions remain.

Acceptance checklist

Before claiming a Mail composition is production-ready:

1. Install Mail alone with Core and with each optional consumer absent.
2. Prove profile scope, visibility, use, test, write, and secret permissions for representative tenant/user/group contexts.
3. Prove policy deny precedence, locked lower limits, approved-profile mode, and the campaign-local-credential fail-closed path.
4. Verify all read/list/capability/audit/log responses contain no plaintext or encrypted password, raw credential token, or consumer-owned inline config.
5. Test DNS rebinding resistance and private/public deployment policy for SMTP and IMAP.
6. Test SMTP acceptance, refusal, temporary/permanent failure, timeout/unknown outcome, and IMAP append success/failure against the target provider.
7. Test Redis worker throttling and prove that independent infrastructure monitoring detects Redis loss; restrict multi-worker delivery during the current silent local-only fallback.
8. Delete tenant and system profiles, inject audit failure, repeat deletion, and prove transactional scrub/rollback/idempotency.
9. Run destructive-retirement preflight on a snapshot and prove credentials are scrubbed/audited before table drop.
10. Pass module permutations, interface/version alignment, WebUI/i18n, full security audit, backup/restore, and target-environment release checks.

Explicitly planned, not yet claimed

• Canonical audit events for profile tests and the remaining profile/policy administration lifecycle, plus an operator-visible Redis-throttling degradation signal.
• Reusable SMTP batch sessions and their final connection/error/isolation semantics (govoplan-mail#16).
• Final Campaign test / single send / single resend semantics; those are a Campaign business-action contract built on Mail transport operations.
• JMAP provider-side mutation, submission, push, thread, calendar, contact, attachment-binary, and automatic background-sync support; read-only mailbox synchronization/search is implemented on the stable IMAP mailbox contract.
• Expanding POP3 beyond the implemented explicit legacy download/import workflow; it has no folder, flag, search, or synchronization contract.
• A full mail client with compose/reply/move/delete/read-state mutation.
• Quick Access may launch the operating environment's configured composer via mailto:. That explicit handoff is not a GovOPlaN Mail delivery: it selects no Mail profile or credential, bypasses no Mail policy, and reports no GovOPlaN delivery result. Recent-message and Drafts links remain read-only deep links into the authorized Mail profile and preserve their Quick Access return context.
• Recovery-ledger adoption for future provider-side move, delete, and flag mutations; no such production path exists in the current read-only mailbox.
• Proof that process-local throttling coordinates multiple workers when Redis is unavailable; it deliberately does not.