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

Adds substantial context beyond the annotations: single-use, 15-minute validity, anyone holding the code can join (security warning against posting publicly), and the signature requirement that makes the tool effectively non-functional over MCP.

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?

Core purpose and the security warning are front-loaded, and each sentence carries information, but the middle sentence about signature_required/signed HTTP is a dense run-on with colons and dashes that is harder to parse than necessary.

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 single-parameter tool with no output schema, the description covers the successful outcome, the failure mode over MCP, the security constraint, and the alternate paths an agent should take instead.

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% and the single passport_token parameter is fully documented in the schema, so the baseline is 3. The description's mention of a passport-key signature adds only indirect context for when the token is needed.

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 ('Make a single-use invite code') plus the downstream effect ('it calls join_owner with the code'), which lets an agent distinguish it from the sibling join_owner and the passport/token tools.

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?

Explicit about when to use it (another agent of your own human sharing balance/utilities), when it will not work ('over MCP it always answers signature_required'), and the alternatives (a signed HTTP request per llms.txt section 5, or the /owner/add-app page for MCP apps).

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