agent-mail

name	agent-mail
user-invocable	false
skill_api_version	1
hexagonal_role	supporting
consumes	["coordination-request"]
produces	["agent-identity","file-reservation","acknowledged-handoff"]
context_rel	[{"kind":"supplier-to","with":"agent-native"}]
metadata	{"capabilities":["agent_mail"],"effects":["write_agent_mail_records","install_precommit_guard","authorized_destructive_reset"],"canonical_status":"canonical","disposition":"keep_optional_adapter","tier":"execution","dependencies":[]}
description	Use Agent Mail as an optional messaging and file-reservation adapter for explicitly coordinated writers. Triggers: "coordinate writers", "reserve files".
practices	["pragmatic-programmer"]
output_contract	factual messaging and reservation adapter results

Agent Mail — optional coordination adapter

Agent Mail carries messages, acknowledgements, identities, and temporary file reservations. It is not a task tracker, queue, proof ledger, or lifecycle controller.

Reservations are advisory: they prevent collisions only because every cooperating writer checks them against the same absolute project path, and one writer registered against a different path resolution makes the whole ledger advisory fiction. Agent Mail enforces nothing on a writer that does not check.

Named failure mode — silence-as-status: reading an unanswered thread as "work stalled" or "work done"; mail silence proves only that no mail arrived.

Anti-pattern: widening or renewing a reservation unprompted when a conflict appears. Corrective: report the conflict to the caller as-is; scope and TTL changes are the caller's call.

Boundary

• Skip Agent Mail for a single writer.
• The caller supplies the absolute project path, agent identities, thread id, participants, paths, exclusivity, reason, and TTL.
• Reservations prevent accidental overlap among cooperating writers. They do not create work ownership or affect Plan, Candidate, or verdict semantics.
• Mail silence proves nothing about work status.
• A message or acknowledgement is evidence that communication occurred, not evidence that a change is correct or complete. The adapter cannot select AgentOps semantics, issue a binding verdict, or turn factory completion into delivery or validation proof.
• Release a reservation, including any force_release, only on the caller's explicit request for that exact reservation. Force-release has no autonomous trigger; a conflict is reported, not force-cleared.
• Agent Mail never selects work, changes tracker state, commits code, validates, integrates, closes, releases, or delivers work.

Modes and authority

Two disjoint surfaces; do not reach the second from the first:

• Coordination mode (default). Register identity, reserve/release the caller's paths, send/read/acknowledge the caller's threads. This is the whole of routine use, and all of it writes durable Agent Mail records.
• Admin / disaster-recovery mode (explicitly caller-authorized only). Installing the git pre-commit guard, doctor repair, backup/restore, and the irreversible clear-and-reset-everything are a separate mode. Each requires the caller's explicit authorization for that specific operation; none is ever performed as a side effect of coordination. clear-and-reset-everything deletes the database and all storage and cannot be undone — never run it, even with --force, without an explicit destructive-reset authorization from the caller.