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

Goes well beyond the annotations: it explains exactly what an idempotent retry returns (same executionId, alreadyEnded: true) and that it never opens a new session, and it discloses the hidden 30-minute auto-TIMED_OUT rule. That timeout behavior is server-side state an agent could not infer from the schema or hints.

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 sentences, each carrying distinct payload: purpose, idempotency contract, timeout behavior. Front-loaded with the core action and no filler.

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?

With no output schema, the description still tells the agent what comes back (executionId, alreadyEnded flag) and covers the edge cases that matter for a mutation: retries and stale sessions. Nothing needed to call it correctly is missing.

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 outcome/error/summary semantics are already documented in the schema, including the failure-requires-error rule. The description only restates the outcome→status mapping; it adds no new parameter guidance, so the baseline 3 applies.

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: "Closes the current agent execution row at the end of a piece of work," plus what it records (SUCCEEDED/FAILED on the audit dashboard). No sibling tool in the list does anything comparable, so the agent can distinguish it immediately.

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?

"At the end of a piece of work" gives a clear timing/context cue for invocation. It does not name any exclusion or point to a counterpart (e.g. task-completion or next_task flows) that would tell the agent when not to close, so it stops short of full alternative routing.

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