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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the bar is lower. The description still earns credit by disclosing the payload contents, notably the bundled 'similar offers' side-content that an agent would not otherwise anticipate and that affects response size.

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?

The functional sentence is front-loaded and wastes no words. The trailing 'Served by r4ck (https://...)' line is boilerplate but short and points to docs, so it costs little.

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 one-parameter lookup with no output schema, describing the returned fields is largely sufficient, and annotations cover the safety profile. Missing are failure behavior for unknown ids and any hint about obtaining a valid id, which matter for a single-resource fetch.

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% and the schema only types the parameter as an integer, so the description must carry meaning. It clarifies that the id identifies an offer rather than a provider or server, which is genuinely useful for disambiguation, but says nothing about id format or where ids come from.

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 pairs a specific retrieval verb with a clear resource and scope: 'One offer by id', and even enumerates what comes back (provider, price history, similar offers). That distinguishes it from list/search style siblings in substance, though no sibling is named explicitly.

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?

'By id' implies the agent must already hold an offer id, which is weak implicit guidance. There is no statement of when to prefer this over r4ck_search_servers or r4ck_cheapest, and no note on what to do if only a query is available.

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