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

Annotations already declare readOnlyHint/idempotent/non-destructive, and the description reinforces with 'writes nothing' without contradiction. It adds real behavioral context beyond annotations: the optional insight is treated as unverified external evidence bound to the exact live thread revision before review, and missing outcomes prompt a request instead of a guess.

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

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

Three front-loaded sentences: purpose, evidence-handling, and write/no-write routing. Efficient overall, though the middle sentence is dense with jargon ('source-minimized', 'live X1 thread revision') that slightly slows comprehension.

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

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

For a 5-parameter tool with a nested object and no output schema, the description covers purpose, the write-free guarantee, the actual closing mechanism, and the missing-outcome edge case. Return-value detail is not required without an output schema, so coverage is nearly complete.

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

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

Schema description coverage is 100%, so the baseline is 3, but the description adds behavioral meaning for parameters: it explains the optional sourceProposal's unverified/hash-bound nature and that an omitted closeoutOutcome causes the tool to ask rather than infer. This meaningfully supplements the structured fields.

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

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

States a specific verb and resource ('Draft a proposed coordination-thread closeout summary with citations...'), and distinguishes itself from the draft_coordination_reply/draft_coordination_thread siblings by being specifically a closeout. It also names the sibling that actually performs the closing (close_coordination_thread).

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

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

Clearly routes the agent: 'This tool writes nothing; closing happens through close_coordination_thread when it is mounted, or in X1,' and says to ask for a missing outcome rather than guess. It gives strong context but never directly contrasts with the other draft_* siblings, so an explicit when-not comparison is absent.

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