List a credential's live registrations

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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable context beyond this: it specifies the nature of the data (live SIP registrations via Kamailio usrloc) and lists possible error codes. This helps the agent understand the behavior without hiding side effects.

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 description is extremely concise: two sentences that front-load the main action and purpose, then provide usage guidance and error information. Every sentence adds value with no wasted words.

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?

Given the absence of an output schema, the description still provides enough context: it explains the command's purpose, usage, how to find required parameters (via trunk_list and trunk_list_credentials), and lists possible errors. For a listing tool with clear annotations, this is complete and sufficient.

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?

Input schema has 100% coverage with descriptive parameter names and descriptions. The description adds minimal extra meaning beyond the schema, such as 'for a credential's AOR', but does not provide additional syntax or format details. Since schema already does the heavy lifting, a baseline score of 3 is appropriate.

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 clearly states the verb ('List') and resource ('current Kamailio usrloc bindings (live SIP registrations) for a credential's AOR'). It distinguishes from sibling tools like trunk_list_credentials (lists credentials) and trunk_revoke_registration (revokes a registration) by specifying the exact output and linking to the latter for contact_id.

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 description gives explicit use cases: to see which devices are registered or to find a contact_id for trunk_revoke_registration. It mentions errors (INVALID_ID, etc.) that imply prerequisites. However, it does not explicitly state when not to use this tool, but the guidance is clear enough for an AI agent.

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