Read a thread

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

Annotations already mark readOnlyHint=true, so the safety profile is covered. The description adds the useful scope that this operation returns messages within a single thread, but does not disclose ordering, pagination behavior, or whether thread metadata is included. No contradiction with annotations.

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 one short sentence with no filler, and it is immediately readable. However, it is a noun fragment rather than a full instructional sentence, which slightly undercuts its clarity.

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 tool with no output schema and undocumented parameters, this description is thin: it does not state the return shape, explain page, or mention ordering/limits. It is workable for a trivial read, but not complete enough for correct calls beyond the required thread_id.

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 0%, so the description must carry parameter semantics, but it only implies thread_id via 'one thread' and never mentions page. An agent has to guess that page controls pagination from its name/default, which is not documented in the description or schema.

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 title supplies the verb and resource ('Read a thread'), and the description narrows the resource to 'Messages inside one thread,' so the tool's purpose is identifiable. It distinguishes from list_threads by emphasizing a single thread, though it does not explicitly name that sibling.

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 sentence tells the agent when to prefer this tool over list_threads, thread_action, or send_message. The singular 'one thread' weakly implies retrieval of a specific thread's messages, but there is no explicit when/when-not guidance.

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