Read a background delegation's result

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds a meaningful behavioral constraint: it errors when the job is still running, telling the agent this is a post-completion read with a specific failure mode. It does not discuss output truncation or pagination, so 4.

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 sentences, zero waste, and the completion precondition is front-loaded. The error condition follows immediately after the main action, keeping the most important routing information prominent.

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 single-parameter read tool with full schema coverage and annotations covering safety, the description supplies the necessary completion precondition and output scope. No output schema exists, so describing the return as 'full output' is appropriately complete.

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 only parameter 'job_id' is documented as 'returned by codex_delegate'. The description adds no additional syntax, format, or constraint beyond the schema, 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 ('Return') and resource ('full output of a finished background delegation'), and the error condition distinguishes it from a status check. It does not explicitly name sibling codex_job_status as the alternative, so it falls short of a 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?

Implies use only after completion via 'finished background delegation' and 'Errors if the job is still running'. However, it does not explicitly tell the agent to call codex_job_status first or name alternatives, so usage is inferable but not spelled out.

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