me.sessions

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint. The description adds owner-scoping behavior ('ids you don't own answer Session not found'), error handling, and details on return structures for both modes. No contradictions.

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 well-structured with a clear first sentence and enumerated modes. It is comprehensive but slightly verbose; however, all sentences contribute necessary context. It could be slightly shorter without losing clarity.

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?

The description covers all necessary aspects: tool purpose, modes, input semantics, output structure, relationships to sibling tools, authentication, plan requirements, and error behavior. Given the complexity and the existence of an output schema, this is fully complete.

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 coverage is 100% for the single parameter session_id, and the schema description is thorough. The tool description echoes this information but does not add significant new semantics beyond what is already in the schema parameter description.

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 that the tool lists or inspects the authenticated user's Governed Sessions, explaining that sessions are durable, owner-scoped containers grouping validation runs. It distinguishes two modes and implies the tool is distinct from siblings like me.validation_history and me.session_event by describing their relationships.

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 explains when to use each mode: no arguments to list all sessions, session_id to inspect a specific session. It also directs the agent to alternatives for fetching full run results (me.validation_history) and for attaching runs (pass session_id to validate tools). Auth and plan requirements are stated.

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