session_end

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

No annotations are provided, so the description carries the behavioral burden. It does disclose three side effects: closing the session, persisting a trace to disk (a side effect with external consequences), and returning the path. However, it doesn't note that this is likely destructive/terminal (session cannot be resumed after), disk persistence implications, or whether closing is irreversible. Moderate disclosure but incomplete for a state-changing operation.

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?

One efficient sentence that front-loads the primary action and lists secondary effects compactly. No wasted words. Slightly better than a bare minimum given it packs three behavioral aspects into a single concise clause, though additional parameter guidance could have been added without excessive bloat.

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 state-changing terminal tool with no output schema and no annotations, the description is thin. It explains the return value conceptually (the path) but not the format, doesn't address reversibility or whether the session becomes unusable, and gives no parameter semantics. Given it's a terminal lifecycle operation among several session tools, more guidance on ordering and implications is warranted.

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 0%, and there's a single required parameter session_id with no type/format detail beyond 'string' in the schema. The description provides zero parameter information—it doesn't explain what session_id identifies, where to obtain it, or any constraints. Since coverage is 0% (below the 50% threshold), the description must compensate, and it fails to do so.

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 the verb and resource: 'Close the session, persist the trace to disk, and return the path.' It describes a specific end-of-session action that distinguishes it functionally from siblings (session_start, session_act) though it doesn't explicitly name them. The three-part behavior (close, persist, return path) is specific and actionable.

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?

No explicit guidance on when to use this tool vs alternatives. With sibling tools like session_act and session_observe present, there's no 'when not to use' or comparison. The description implies it's used at the end of a session lifecycle, but this is implicit rather than stated. No exclusions or ordering requirements (e.g., must session_act first) are provided.

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