Check the Codex CLI installation

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 that it inspects the installation and reports exact fix steps, and reinforces the no-change boundary, but does not disclose caching behavior or output format. With annotations carrying the safety load, this is a useful but not exceptional addition.

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?

Three sentences, front-loaded with purpose, then usage triggers, then the scope boundary. Every sentence earns its place with no redundancy.

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 simple read-only diagnostic with one optional parameter and no output schema, the description covers purpose, usage triggers, and boundaries sufficiently. It even indicates that failure produces exact fix steps, so an agent can call it correctly without more detail.

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% for the single 'refresh' parameter, so the schema already explains its meaning. The description adds no parameter-level detail, 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 and resource: checks whether the local Codex CLI is installed, recent enough, and signed in, and reports exact fix steps. Distinguishes from siblings by framing itself as the diagnostic to run when other tools report CLI unavailability or before relying on delegation.

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?

Explicitly says when to run: when any other tool reports the CLI is unavailable, or before relying on delegation for the first time. Also sets a boundary ('never installs or changes anything'), which tells the agent not to use it for installation. The alternative (delegation) is implied rather than named, but the context is clear.

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