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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description does not need to repeat safety. It adds the useful detail of 'bounded, paginated page,' which informs the agent that not all turns are returned at once. It does not disclose auth requirements or error behavior, but the strong annotation base makes a 4 appropriate.

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?

A single, concise sentence that front-loads the action and scope with no fluff. However, it is too short to carry all necessary information, so it is concise but under-specified rather than optimally structured.

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?

Despite having an output schema that covers return values, the description is insufficient for an agent to call this correctly: no parameter semantics, no pagination mechanics, and no guidance on when to use it versus siblings. The agent would need to infer how to set cursor and turn_limit, and what include_turns does, making the description incomplete.

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%, meaning no parameter descriptions exist in the schema. The description does not explain thread_id, cursor, turn_limit, or include_turns. The mention of 'bounded, paginated' hints at cursor and turn_limit but does not define their behavior, so the agent must guess parameter semantics—a significant gap.

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 description clearly states this tool reads thread metadata and a bounded, paginated page of turns. It distinguishes from list_codex_threads (which likely lists thread summaries) and get_codex_turn_status (which targets a single turn's status) by specifying the resource and scope. However, it does not explicitly name a sibling alternative, so it stops short of a perfect 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?

The description implies this tool is for reading thread content, but provides no explicit guidance on when to choose it over list_codex_threads, resume_codex_thread, or get_codex_turn_status. With many sibling tools, a clear 'use this when...' statement is absent, leaving selection to inference.

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