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

readOnlyHint=true already covers the safety profile, so the bar is lower. The description adds that the lookup is scoped to the invoking key's environment and that only the currently-serving deployment is returned, which is genuine behavioral context. It does not mention auth/scope failure modes or caching, so it stays mid-range.

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 tight sentences with the resource and scope front-loaded; the trailing API path is arguably redundant with the title but is cheap and useful for verification. No filler.

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?

With no output schema, the description compensates by naming the fields returned (version, git ref, status), which is exactly what an agent needs to decide whether to call it. Remaining gaps (error behavior when no deployment exists) are minor for a zero-param read.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly signals that no identifier is needed because the environment is derived from the API key, which is the one meaningful semantic an agent might otherwise hunt for.

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 (fetch) and resource (the current deployment), scopes it to the key's environment, and enumerates the returned fields (version, git ref, status). No sibling tool retrieves deployments, so the differentiation from the list is implicit but unambiguous.

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?

Usage is implied rather than stated: an agent can infer this is the tool for checking what is live in the current environment. There is no explicit when-to-use/when-not guidance and no named alternative (there is no sibling that reads deployments, so none is needed). Adequate but unelaborated.

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