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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the exact field set returned, the numeric format of deployment_commit (40-char SHA or null), the prohibition on credentials in tool arguments or results, and the deliberate exclusion of registration paths. It stops short of discussing nothing important, but the security and scope disclosures are strong.

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?

Front-loaded with the actionable rule, then the return-field list, then the security/registration caveats. Every sentence carries information, though the middle section is dense and could be tightened slightly without loss.

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?

With no output schema, the description carries the full burden of describing return values and does so explicitly, enumerating every fact served. The credential-handling rule and the deliberate exclusion of registration close the remaining gaps for a zero-parameter read tool.

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 tool takes zero parameters with additionalProperties false, so there is nothing for the description to disambiguate. Baseline 4 applies; the description correctly does not invent arguments and even warns against passing credentials as arguments.

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?

Opens with a specific verb and sequencing ('Read after front_door and before any payment') and then enumerates exactly what is returned: domain, deployment_commit, Base network, USDC contract, treasury, fees, identity feature state, no-token statement. This distinguishes it from siblings like front_door, treasury, and merchants without the agent needing to open any schema.

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?

Gives an explicit ordering rule relative to front_door and payment, and goes further to state what its job is NOT: merchant registration and key rotation are 'deliberately never an MCP tool' and are browser-only, with a named out-of-band path (POST /api/register or /api/rotate) for non-browser clients. Nothing 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.