session.resume

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

The description says each call logs another session.resumed event, which contradicts the idempotentHint=true annotation. Although it otherwise discloses useful side effects and return shape, the annotation contradiction is a serious inconsistency.

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 front-loaded, with the core action first and usage guidance and return shape afterward. All three sentences carry relevant information without waste.

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 single-optional-parameter tool with no output schema, the description supplies enough context: side effects, return shape, and when to use it versus context.get. The remaining issue is the idempotency contradiction, not missing context.

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 100%, and the schema already documents the agent parameter, including its default. The description adds little beyond saying the calling agent is attached, so baseline 3 is appropriate.

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 states a specific verb and resource: reopening the most recent session, marking it active, attaching the agent, and logging an event. It also names the return shape and distinguishes the action from context.get for an already active 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?

It explicitly says when to use it: taking over from another agent or reopening a completed session. It also gives the alternative for an already active session, context.get, so the routing decision is clear.

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