Stop session

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

Annotations only declare non-readonly, non-destructive, non-idempotent; the description adds real behavioral context beyond that: the timer keeps running for other sessions, outcome=done completes the linked plan item or path step (a write side effect despite destructiveHint=false), and an ended session is refused. That is exactly the kind of side-effect disclosure an agent needs before invoking.

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 short sentences, zero filler, and the core action plus target is front-loaded before the side-effect and refusal details. Every sentence carries distinct information.

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 mutation tool with no output schema, the description covers the important behavior: target resolution, plan-item/path-step side effect, timer semantics for other sessions, and refusal behavior. It stops short of describing the other outcome values or the attention_share correction, which is the only meaningful gap.

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 only 25%, so the description has to carry weight. It explains the meaning of outcome=done and clarifies that session_id is optional and defaults to this connection's session, but says nothing about partial/abandoned or about attention_share (which only has a terse schema description). Two of four parameters remain under-explained.

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 ('Stop a running session') plus the target resolution ('this connection's, or session_id'), which lets an agent separate it from start_session, stop_timer, and delete_session. It also names the sibling it is not for one case (edit_session), so it is distinguishable without opening any schema.

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?

Explicitly gives the when-not case: a session that already ended is refused and edit_session should be used instead. It does not, however, contrast with stop_timer (stopping just the timer) or explain what to do when no session is running, so one boundary is left implicit.

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