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

With readOnlyHint=true already declaring the safety profile, the description adds the upstream endpoint and the filter-passing mechanism, which is moderate value. It still says nothing about result ordering, pagination behavior, or thread grouping that an agent might care about.

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?

Three short sentences, front-loaded with the core purpose and with no filler. The API-route sentence is slightly redundant with the tool name but can aid agents mapping to the raw endpoint.

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 simple read-only list tool with no output schema and fully documented typed parameters, the description covers purpose, endpoint, and filtering adequately. The open-ended `params` object remains loosely specified, but the schema carries most of the load.

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 coverage is 100%, and limit/offset are fully documented in the schema, so the baseline is 3. The description adds only a single example filter (booking_id) for the open-ended `params` object, which is marginal extra meaning beyond what the schema states.

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?

"List messages from guest-communication threads" gives a specific verb and resource, and naming the API route (GET /v2/messages) reinforces the read scope. It is distinct from create_message, but it doesn't explicitly differentiate itself from closely related read siblings like list_inquiries that also surface guest communication.

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 implies a standard listing use case and offers a filtering hint ("Use `params` for documented filters (e.g. booking_id)"). However, it never states when to choose this tool over list_inquiries or other siblings, nor any exclusions or prerequisites.

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