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

With annotations already declaring readOnlyHint, idempotentHint, and non-destructive behavior, the description adds useful context: it lists the exact returned fields and notes that an api_key (issued in the admin panel) is required. It does not mention rate limits or error behavior, but the added return-value and auth details are valuable beyond the annotations.

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?

Two sentences, front-loaded with the returned information and followed by the mandatory auth note. There is no redundant or filler content.

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 the return payload (since no output schema exists) and the auth requirement, and annotations cover the safety profile. The only gap is that session_id is not described anywhere, but for a simple read tool this is a minor omission.

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 50%: api_key has a schema description, session_id does not. The description reinforces api_key semantics by stating it is required and where it can be obtained, which adds meaning beyond the schema. However, session_id remains undocumented in both schema and description, so compensation is only partial.

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 returned resource (session status) and enumerates the exact fields returned (active/ended, queue length, connection duration, expiration). This distinguishes it from siblings like list_sessions (which lists many) and end_session (which mutates state).

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?

Usage is implied by the need to know a specific session's state, but the description never states when to use this tool versus alternatives such as list_sessions or end_session. No exclusions or explicit routing guidance is provided.

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