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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a return-content hint (stack trace and metadata), which is useful given there is no output schema, though it stops short of describing detail levels, cost, or error behavior for a missing ID.

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 short sentences, front-loaded with the verb and scope. The second sentence is slightly padded ('like metadata') but is justified because no output schema exists to convey what is returned.

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 single-item fetch with strong annotations, the essentials are present: what it returns and that it targets one record. Missing is any differentiation from logs_get_details and any statement about behavior when the messageId is not found, which matters since no output schema exists.

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%, so logId, messageId, and the fields parameter are already fully documented in the schema, including the token-saving advice and enriched-field caveats. The description adds nothing beyond 'by ID', so the baseline of 3 applies.

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?

States a specific verb (Fetch) and resource (a single log message) scoped by ID, which cleanly separates it from list-style siblings like messages_list and messages_list_recent. It does not, however, differentiate itself from the similarly named logs_get_details, which an agent could easily confuse it with.

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 tool versus alternatives such as messages_list, logs_get_details, or messages_list_recent. The 'by ID' phrasing implies single-item retrieval, but no when-to-use or when-not-to-use conditions are stated.

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