x402_session_end

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behaviors: it's a destructive operation (closes a session), has side effects (x402_session_fetch will return an error), and mentions security implications. It doesn't cover rate limits or authentication needs, but provides substantial context beyond basic function.

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 efficiently structured in two sentences: the first states the core action and immediate effect, the second provides usage context. Every phrase adds value without redundancy, making it front-loaded and appropriately sized for the tool's complexity.

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?

Given the tool's moderate complexity (destructive operation with security implications), no annotations, and no output schema, the description does well by explaining the action, effects, and usage scenarios. It could be more complete by mentioning authentication requirements or response format, but it covers the essential context for safe use.

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 100% description coverage, with the session_id parameter fully documented in the schema. The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints. This meets the baseline for high schema coverage.

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 specific action ('explicitly close') and resource ('an x402 V2 session'), distinguishing it from siblings like x402_session_fetch, x402_session_start, and x402_session_status. It precisely defines what the tool does beyond just restating the name.

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 explicitly states when to use this tool ('before it expires naturally', 'useful for security hygiene or when you know a session is no longer needed') and provides a clear alternative (letting it expire naturally). It also mentions the consequence for x402_session_fetch, guiding usage relative to siblings.

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