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

No annotations are provided, so the description carries the full burden. It usefully discloses that the tool is 'Free, no auth' and that it produces a session token for subsequent authenticated calls. It does not mention token expiry or invalidation of prior sessions, but for a login completion step this is reasonably transparent.

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 verb phrase, and no filler. Every clause adds value: the action, the output, the token usage, and the cost/auth status.

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 two-parameter, no-output-schema tool, the description fully covers the workflow: it explains the input origin, the output token, and how to use the result. No significant information gap remains.

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?

The schema already describes both parameters accurately and completely (100% coverage), so the baseline is 3. The description mentions the 'signed SIWE message' but adds little about the signature parameter beyond what the schema provides.

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 opens with 'Finish wallet sign-in' and immediately specifies the action: 'exchanges the signed SIWE message for a cl_sess_… session token'. This clearly distinguishes the tool from its sibling start_siwe_login, which initiates the sign-in flow.

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 implies when to use it ('Finish wallet sign-in') and gives post-use guidance ('use it as the Authorization bearer on every authenticated tool'). It does not explicitly name alternatives or state when not to use, but the reference to a signed SIWE message makes the prerequisite and context clear.

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