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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds the 'No live eligibility check' note, which is not covered by annotations, and clarifies that the visible code can be null. This provides extra behavioral context beyond the structured metadata.

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 description is extremely concise, consisting of three short sentences that front-load the main purpose and include the key filtering option. Every sentence contributes value with no fluff.

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?

Given an output schema exists and read-only annotations are present, the description covers the essential return contents (offer type, code, link, conditions) and notes the absence of live eligibility checks. Pagination behavior is left to the schema, which is acceptable.

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 only 33% (category has a description). The description mentions the optional category filter but does not elaborate on limit or offset parameters, which remain undocumented in both schema and description. It adds minimal meaning beyond the schema for category and nothing for pagination.

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 clearly states the tool lists brands with specific attributes (public offer type, visible code or null, lifetime signup link, full conditions) and an optional exact category filter. This distinguishes it from siblings like list_campaigns (campaigns) and search_codes (codes), making the purpose 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?

The description implies usage for browsing brands but does not explicitly mention when to use this tool versus alternatives like search_codes or list_campaigns. There is no exclusion or routing guidance, so an agent must infer from the purpose.

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