codex_resume

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

With no annotations, the description carries the behavioral burden and does meaningful work: it clarifies that resume does not itself continue the work, only attaches the thread, and that it depends on reconnection. Minor omissions such as idempotence or error behavior exist, but the key behavioral distinction from codex_message is disclosed.

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 with no filler. The main action and the crucial routing hint are front-loaded, and every clause adds value.

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, low-complexity tool, the description is complete enough: it states what it does, when to use it, and what to use instead for continuation. No output schema or annotation exists, but none is required for the agent to select and invoke the tool correctly.

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 compensate for the lone threadId parameter. It adds the meaning 'a saved Codex thread,' which helps, but it does not explain where the threadId comes from or what qualifies as saved. This is partial compensation rather than full.

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 uses a specific verb ('Attach') and resource ('a saved Codex thread'), and explicitly contrasts with codex_message ('to continue its work'). This clearly tells an agent what codex_resume does and how it differs from the sibling that continues work.

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?

It states the condition ('after reconnecting'), the action ('attach a saved Codex thread'), and the alternative ('Use codex_message to continue its work'). An agent receives explicit routing guidance without needing to infer.

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