session_end

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

Annotations indicate idempotent and non-destructive behavior, which the description does not contradict but also does not elaborate on. The description does not disclose what 'ended' entails (e.g., state changes, cleanup). With annotations present, the description adds minimal behavioral context beyond the structured data.

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 extremely concise (one phrase) and front-loads the core purpose. It is efficient with no wasted words, though it could afford a bit more detail without losing brevity.

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 tool with one optional parameter and an output schema, the description is adequate but lacks context on typical usage scenarios or post-conditions. It does not explain the summary's usage beyond being optional.

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 description mentions 'optional terse summary' which maps to the summary parameter, but does not explain its purpose or format. With 0% schema coverage, the description adds some meaning but not enough to fully compensate for the lack of parameter documentation.

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 action (mark session ended) and the resource (current session). It includes the optional summary parameter. However, the verb 'Mark' is slightly vague; 'End' would be more direct. It distinguishes from siblings like 'close_thread' by focusing on session termination.

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 provides no guidance on when to use this tool, such as prerequisites or conditions for ending a session. It does not mention alternatives or exclusions, leaving the agent to infer usage context from the tool name alone.

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