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

The annotations already establish read-only, idempotent, non-destructive behavior. The description usefully adds that no carrier settings change, number purchase, or phone call is triggered, and notes the linked-call-evidence requirement without contradicting those annotations.

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 three short sentences are economical, and the side-effect limitations are easy to scan. However, the opening uses its prime position on vague "Manage ... canonical service" wording rather than the actual retrieval operation.

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 lookup with three undocumented parameters and no output schema, the definition leaves essential gaps: what test status or verification information is retrieved, how the required IDs relate, and how linked call evidence affects the result. The safety caveats are helpful but do not make selection and invocation sufficiently complete.

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?

With 0% schema description coverage, none of setup_id, attempt_id, or project_id is explained in the schema. The description does not compensate by mapping the IDs to a setup and test attempt, explaining where to obtain them, or clarifying how project_id scopes the lookup.

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 scopes the domain to an existing-number forwarding setup, but "Manage" does not state that this tool retrieves a specific forwarding test attempt. It therefore fails to distinguish the operation clearly from get_forwarding_setup, start_forwarding_test, or update_forwarding_setup.

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?

There is no explicit guidance on when to use this lookup instead of start_forwarding_test, cancel_forwarding_test, or get_forwarding_setup. The linked-call-evidence statement hints at a verification prerequisite, but does not explain when to call this tool or what state the test must be in.

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