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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description still adds real value by disclosing what content is returned and by flagging hedges ('where verified', 'remaining limitations') plus the explicit 'never creates or verifies purchases' boundary, which tells the agent the result cannot be treated as purchase confirmation.

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 compact sentences with the scope constraint front-loaded and a list of surfaced fields that scans quickly. The closing negation is slightly redundant against the readOnly annotation, but it is short and reinforces rather than pads.

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 does the right thing by enumerating returned content, which is the main completeness need here. However, for a tool with two entirely undocumented parameters, it leaves the agent guessing about the id format and the purpose of the language argument, so the definition is adequate but not sufficient.

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%, so the description must carry the semantics of both parameters and largely does not. 'One exact offer' hints that id identifies the offer, but the id's format constraints (slug pattern, 120-char cap) go unmentioned, and the language enum is not addressed at all — worse, 'the deliverable language' in the description could be misread as the language parameter rather than an output field.

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 names a specific verb and resource: a 'public read-only purchase guide for one exact offer,' and enumerates what it surfaces (unit amount, official URL, deliverable language, kit contents, prerequisites, limitations). It does not explicitly contrast itself with the closest siblings such as acorn_offer_details or acorn_commercial_boundaries, so an agent must infer the boundary.

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 only implied: 'for one exact offer' signals that an offer id is required and that this is a pre-purchase inspection step. There is no explicit statement of when to choose this over acorn_offer_details or acorn_compare_offers, and no stated exclusions or prerequisites for calling it.

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