MCPFax Agent Continuity

Mark a task done

inbox_ack

DestructiveIdempotent

Acknowledge a task you finished. FREE and idempotent — acking twice is not an error. If the task was a repeating schedule, the next occurrence is queued now. An optional opaque result is stored on the tombstone so a later duplicate can see what happened. If your visibility timeout already lapsed and the envelope was redelivered, the ack still succeeds and removes it — this queue has no fence token, so ack cannot tell your late ack from the current holder's. Ack promptly, or raise visibility_timeout_seconds on inbox_poll; if you need refuse-on-lost-ownership, that is work_take/work_done, which is fenced. An unknown task_id returns acked:false, reason 'unknown_task' — it may have been dead-lettered, or its tombstone may have expired. FREE — this tool never charges. Authenticate with Authorization: Bearer , or pass agent_key as an argument if your host cannot set headers. Equivalent HTTP route: POST /v1/inbox/ack.

Input Schema

TableJSON Schema

Name	Required	Description
`result`	No	Optional opaque outcome blob. Example: '{"ok":true}'.
`status`	No	'done' or 'failed'. Default 'done'. Recorded, not interpreted. Example: 'done'.
`task_id`	Yes	The task_id from inbox_poll. Example: 'tsk_...'.
`agent_key`	No	Your agent_secret, if your MCP host cannot set the Authorization header. Prefer the header.

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description richly discloses behaviors beyond the annotations: idempotent double-ack, repeated-schedule queueing, tombstone result storage, redelivery handling without fence tokens, unknown-task returns, and FREE/no-charge. These add substantial context not present in the annotations, and there is no contradiction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Though the description is long, every clause contributes critical operational detail. It front-loads the main action and then systematically covers idempotency, scheduling, redelivery, fencing, unknown tasks, cost, and authentication—no filler or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description addresses all significant edge cases an agent would need: double-ack, repeated schedules, redelivery without fence tokens, unknown task_id, costing, and auth. Given the absence of an output schema, it also discloses the unknown-task return. This is a model of completeness.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes all 4 parameters with 100% coverage, so the baseline is 3. The description adds extra value by explaining that the result object is stored on the tombstone, the status field is recorded but not interpreted, and agent_key is an alternative to the Authorization header, elevating it above the schema alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with 'Acknowledge a task you finished,' which clearly states the verb and resource. It distinguishes the tool from siblings by explicitly naming work_take/work_done as the fenced alternative and referencing inbox_poll for timeout adjustments, making the purpose unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit usage guidance: 'Ack promptly, or raise visibility_timeout_seconds on inbox_poll' and 'if you need refuse-on-lost-ownership, that is work_take/work_done, which is fenced.' This directly tells the agent when to use this tool versus alternatives, satisfying the highest bar.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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TDQS

A4/5.0

Disambiguation5/5

Every tool targets a clearly distinct mechanism—barriers, budgets, checkpoints, claims, heartbeats, inboxes, leases, work queues, etc. Even closely related pairs like claim/complete, work_done/inbox_ack, and barrier_status/work_status are explicitly differentiated in their descriptions, so an agent can reliably select the right tool.

Naming Consistency4/5

The dominant pattern is object_verb (e.g., checkpoint_get, work_push, seen_add, lease_release), which is consistent and readable. A few single-word verbs (claim, complete, send) and noun-only names (resume_packet, retry_state, whoami) break the pattern, but they are few and still intuitive.

Tool Count2/5

With 33 tools, the surface is well beyond the 25-tool threshold for 'too many' and will feel heavy for agents to explore, even though the tools are organized into subdomains. The scope is broad, but the sheer number makes the server less approachable and increases the chance of misselection.

Completeness5/5

The tool set provides thorough lifecycle coverage across its domains: checkpoints get/put, work queue push/take/done/fail/status, inbox poll/ack/nack/schedule, lease acquire/renew/release, barrier create/signal/status, dedup add/check, watermark get/set, retry state, budget check/record, and idempotency claim/complete. There are no obvious dead ends or missing essential operations.

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