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

readOnlyHint=true already tells the agent this is a non-destructive read, and the description adds only the REST endpoint, which is restatement rather than new behavioral context. It says nothing about what happens when the id does not exist, whether errors are raised or null returned, or rate-limit behavior.

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 the action front-loaded and no filler. The endpoint line is compact and useful for orienting to the underlying API, though it is close to redundant with the tool name.

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 single-resource read with full schema coverage and read-only annotations already present, the definition supplies what is needed to call it correctly. The only meaningful omission is failure semantics for a nonexistent id.

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?

Only one parameter and schema description coverage is 100%, so the schema fully documents 'id' as the numeric resource id. The description's 'by id' adds no syntax, range, or format detail beyond that, making the baseline 3 appropriate.

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 (a single resource identified by id), and the endpoint mapping 'GET /volumes/{id}' pins it to volumes, so it is distinguishable from siblings like hetzner_list_volumes. The generic phrase 'a single resource' is weaker than the title 'Get one volume', but the endpoint line resolves the ambiguity.

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?

No guidance on when to use this versus hetzner_list_volumes or other get_* siblings, and no mention of prerequisites such as needing a valid volume id. The agent must infer the single-vs-list distinction from the name alone.

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