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

Goes beyond the destructive/idempotent annotations by disclosing that the call fully replaces the allow-list (not merges), the accepted origin format, and the empty-array escape hatch. It also flags the side effect for ask-policy connections (human approval link), which annotations alone cannot convey.

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 dense sentences, front-loaded with the core action and immediately followed by the format and edge-case semantics. No filler.

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 destructive, single-parameter mutation with an output schema present, the definition covers the replacement semantics, accepted input, and side effects adequately. The only omission is the array size limit, which is minor and already in the schema.

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 0%, so the description must carry the parameter meaning, and it does: it defines the expected value shape ('bare http(s) origins') and the special empty-array case. It omits the maxItems=20 cap documented in the schema, leaving one small gap.

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: 'Replace the publishable-key origin allow-list'. An agent can infer this is the write counterpart to the sibling fillo_get_origins, though the description never names that sibling explicitly.

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 only implied through the replace semantics and the 'empty array allows any' note. There is no explicit statement of when to use this versus fillo_get_origins or under what conditions an agent should modify origins.

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