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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false; the description is consistent with that and adds real context: closure is logged with residue in arroway_log, the note should name what emptied the handoff, and destructive disposal is reserved for a human in the panel. It does not say whether a closed handoff can be reopened or what the response contains, but the safety profile is well covered.

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?

The core action is front-loaded in the first clause, and no sentence is pure filler. However, the prose is stylized and oblique ("the residue," "what an open handoff exists to fix"), and the third sentence packs three separate rules into one run-on, adding parsing cost for an agent.

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 three-parameter mutation with annotations and no output schema, the description covers who may close, when, and the required companion logging call. Minor gaps remain: it implies the note is expected even though the schema marks it optional, and it does not state what happens on success or when a handoff is already closed.

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 coverage is 100%, so project, handoff, and note are already documented in the schema. The description adds only marginal meaning, mainly that the note should "name what emptied it" when closing someone else's handoff; the handoff handle and project slug get nothing beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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: "Close an open handoff when its work is DONE." It also distinguishes closing from discarding ("discarding a handoff is the human's gesture, in the panel"), which is a useful boundary. It does not name sibling tools such as arroway_retire or arroway_withdraw, so the differentiation is conceptual rather than explicit.

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?

Gives explicit conditions: close when the work is done and "alongside the arroway_log entry," including someone else's handoff when your work emptied it. It also gives a clear exclusion — a handoff still carrying real work "must never" be closed by a passer-by. The missing piece is routing against the other lifecycle siblings (retire, withdraw, pass) that an agent would need to choose between.

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