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

With readOnlyHint and idempotentHint already supplied, the safety profile is covered. The description's real contribution is the return payload inventory, including the status enum values (active, reserved, sold), which is genuinely useful because there is no output schema. It does not say what happens for an unknown or stale id (error vs empty result), which is the main behavioral gap.

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?

A single front-loaded sentence with no filler; the trailing list is dense but each item is information-bearing for an agent reasoning about whether this tool returns what it needs. Slightly long as one clause chain, which keeps it just shy of a 5.

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 read tool with no output schema, the description adequately explains what comes back and how to obtain the id. Only the not-found/error behavior is left unspecified, which is a minor omission given the read-only, idempotent annotations.

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 coverage is 100%; the description restates the id's provenance ("returned by search_offers") but the schema property already says "Offer id from search_offers," so it adds no new meaning. Baseline 3 is correct where the schema carries the parameter semantics.

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 ("Full details of one product, service or catalogue item of this brand") and pins the key differentiator versus search_offers: this returns everything for exactly one item, enumerated as description, price, availability, status, attributes, photos, URL, last-updated and promotions. An agent can distinguish it from search_offers and get_promotions without opening a schema.

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?

The phrase "by the id returned by search_offers" makes the intended workflow explicit: search first, then hydrate a single offer here. It stops short of stating exclusions (e.g. don't loop this for bulk retrieval) but the usage context is unambiguous.

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