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

Goes well beyond the annotations: it discloses probing behavior (one unpaid request per scheduled interval), safety constraints (never a paid call, no tool invoked), data retention ('we keep only the address'), and the return value (service id and page). This is consistent with readOnlyHint=false (it creates a directory entry) and idempotentHint=true (duplicate submissions converge on the same listing).

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?

The accepted inputs are front-loaded and every clause carries information (coverage policy, no-cost guarantee, retention, return value). Slightly compressed phrasing ('we check it like a service from a registry') costs a little readability but no waste.

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 three-parameter mutation tool with no output schema, the description supplies the missing return contract (service id and page), the acceptance criteria gating listing, and the no-cost guarantee. Nothing needed to call it correctly is 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% and each parameter already carries an explanation, so the baseline is 3. The description corroborates that a bare address suffices and that 'no key needed', but adds no syntax or format detail beyond the schema.

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?

Uses a specific verb ('submit') plus the exact resource types accepted (paid API endpoint answering HTTP 402, remote MCP server, A2A agent card) and scopes it to entries not yet listed. An agent can distinguish this from search_services/get_service without opening a 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?

The phrase 'that we don't list yet' clearly establishes the submission context, and 'no key needed' removes a common pre-flight question. It does not explicitly name search_services as the check-first alternative, so the when-not is implied rather than stated.

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