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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=true), so the bar is lower. The description still adds real context beyond them: the name is always transmitted because the API requires it, empty-list fallback to org policy, and omission semantics. It does not, however, explain the destructive aspect the annotations imply.

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?

A single dense paragraph with the operation class front-loaded ('WRITE:'), the primary and secondary actions in order, and the endpoint last. No filler sentences.

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 no-output-schema mutation tool whose annotations cover safety, the description supplies action scope, optionality, fallback behavior, and the endpoint. It omits response format and any auth/permission requirements, but nothing essential for correct invocation is missing.

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%, so the schema already documents all three parameters including the enum values and the []/omit semantics. The description mostly restates the recording_access_policy behavior and only genuinely adds the 'name is always sent' constraint, so baseline 3 applies.

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 two specific operations (rename a session, set recording access) on a named resource and flags the operation class with 'WRITE:'. This is clearly distinguishable from the read-oriented siblings (get_session, list_sessions).

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 clarifies optional-vs-required behavior: recording access is optional, an empty list falls back to org policy, and omitting it leaves the value unchanged. It gives no explicit when-to-use-vs-alternative routing, but the read/write split against siblings is implied by 'WRITE:'.

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