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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real context beyond that: the absence of any list endpoint and where a valid id originates. It doesn't mention error behavior for stale/unknown ids, which keeps it below 5.

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?

Two tightly written sentences, front-loaded with what is returned, followed by the id-provenance caveat. No filler, though the trailing 'GET /messages/{id}.' is redundant for an agent that cannot issue raw HTTP.

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 one required parameter, full schema coverage, and no output schema, the description supplies exactly the missing pieces: the shape of the returned message and how to legitimately obtain the id. Nothing an agent needs to call this 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 coverage is 100% and the single parameter is fully documented in the schema with the same 'from the reply of a send call or from a webhook' provenance. The description restates that rather than adding new syntax or validity details, which is the baseline-3 case.

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?

Names a specific verb and resource ('One chat message by id') and enumerates the payload fields the caller gets back (type, text, visitor id, agent id, timestamp, receivedFrom), so the agent knows exactly what it retrieves. It doesn't explicitly declare a boundary against chatra_get_pushed_message, the nearest sibling, so it falls short of a full 5.

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 a genuine prerequisite: the id must come from a send call or a webhook because Chatra has no conversation-listing endpoint. That tells the agent when this tool is callable at all. It stops short of naming alternatives (e.g. get_pushed_message) when the id refers to a pushed message.

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