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

Annotations only declare readOnlyHint=true; the description goes further by stating the exact return shape (channel, status, verified_at) and the SEC-PM-006 constraint that no identifier is ever returned. That security/return-scoping detail is exactly the kind of context annotations cannot carry. Minor gap: no pagination or volume behavior.

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?

Purpose and return contract are front-loaded in the first sentence, and the auth note is clearly separated. The ACCESS paragraph is slightly verbose with the parenthetical UI path and the start_login caveat, but every sentence carries information.

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?

Despite no output schema, the description enumerates the returned fields and flags the identifier omission, and it covers the authentication prerequisite. For a two-param read tool this is close to complete; only pagination/ordering details are absent.

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% with both required params documented, so the schema carries the burden. The description adds nothing about the id/member_id format (24-char hex) or relationships beyond what the schema already states, 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?

States a specific verb and resource ('List a Circle member's channels') and even previews the returned fields, which lets an agent distinguish it from the broader member-listing siblings. It does not, however, explicitly contrast itself with near-neighbors like list_circle_members or add/remove_circle_member_channel.

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 ACCESS block gives a real precondition (must be authenticated with a Proof account, and start_login will not unlock it), which is useful. But it offers no guidance on when to prefer this tool over list_circle_members or get_circle, so alternative routing is left to inference.

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