session_end

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

Since no annotations are provided, the description carries the full burden of disclosing behavior. It transparently mentions the closing of the session, persistence to disk, and returning the path. It does not state that the session becomes invalid after closing, but 'close' implies this, and the key side effects are 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 description is a single, well-structured sentence that sequentially lists the actions: close, persist, and return. Every word adds value, and it is instantly readable. There is no redundancy.

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 simple one-parameter tool with no output schema, the description sufficiently covers the purpose, side effects, and return value. It could be more explicit about the session_id parameter and the irreversible nature of closing, but it provides enough information for an agent to invoke the tool correctly in most contexts.

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?

The input schema has a single required parameter, session_id, with no description, and schema coverage is 0%. The description indirectly maps the parameter by referring to 'the session', suggesting that session_id identifies which session to close. This provides some context but does not explicitly describe the parameter's format or constraints.

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?

The description clearly states a specific action ('Close the session') and its side effects ('persist the trace to disk', 'return the path'). It distinguishes this from sibling tools like session_start, session_act, session_observe, and qa_get_trace by focusing on the terminal action of a session.

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?

The description implies the tool is to be used when ending a session and saving its trace. While it does not explicitly mention alternatives or exclusions, the context is clear: 'Close the session' is a definitive action that an agent would choose when finishing a session. The sibling tools cover other phases, making the usage context evident.

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