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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds only the REST endpoint mapping (GET /conversations/{id}), which gives no new behavioral context such as error behavior for invalid/missing ids or the shape of the returned conversation.

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 actual purpose; the endpoint mapping is slightly redundant but compact. Nothing is padded.

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 one-parameter read tool with readOnlyHint and full schema coverage, the essentials are present. However, there is no output schema, so the description could have briefly indicated what a fetched conversation contains and how it differs from list results; that gap keeps it at minimum-viable.

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% and the single parameter is already documented as a UUID-like resource id. "by id" in the description adds nothing beyond the schema, so the baseline 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?

Specific verb+resource: "Get a single conversation by id" clearly states the operation and singular scope, implicitly distinguishing it from missive_list_conversations. It stops short of naming or contrasting with siblings like missive_get_message or missive_list_conversation_messages.

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?

No when-to-use guidance, no exclusions, no pointer to alternatives for fetching related resources (messages, drafts, comments). The agent must infer that this is the single-item counterpart of missive_list_conversations.

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