Agent Mail Agent Skill

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.

• 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.

Surfaces

Use the MCP tools when they are present. Otherwise use the self-describing am

CLI. Discover current syntax with am mail --help,

am file_reservations --help, and related group help; do not infer commands

from remembered aliases.

One-shot use

• Confirm that multiple explicitly coordinated writers share the repository.
• Register the caller-supplied identity against the same absolute project path.
• Reserve only the supplied paths, with a bounded TTL.
• Report conflicts without waiting, narrowing scope, or changing the plan.
• Send the supplied message once and record its id.
• Read or acknowledge only the requested thread.
• Release only reservations the caller explicitly asks to release.

Output

Return the project, identity, thread/message ids, reservation ids and paths

(with their TTLs), conflicts, and timestamps. The caller owns all subsequent

decisions.

Terminal outcomes are explicit, never silent:

• Adapter unavailable — neither the MCP tools nor the am CLI is present:

report that Agent Mail is unavailable and stop. Do not fall back to

hand-written coordination or treat the absence as "no conflicts".

• Reservation conflict — report the conflicting reservation as-is; do not

narrow, widen, renew, or force-release it.

• Timeout / degraded surface — report the operation as timed out or degraded

with what was and was not observed; a timeout is evidence, not "done".

• Cleanup — reservations released this session are listed by id; any left

in place (still holding a TTL) are named so the caller can see what remains.

References

• CLI and MCP surface notes
• Coordination patterns
• Troubleshooting