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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description adds that each result includes eligibility, requirements, and links, which is slight extra context. It says nothing about result volume, ranking, or empty-result behavior beyond what the annotations already imply.

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 sentences, front-loaded with the scope definition, with no filler language. The second sentence about result contents leans on information the output schema likely already provides, keeping it just short 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?

Scope and coverage are clear and an output schema exists, so return values need no explanation. For a 7-parameter discovery tool sitting among similar search and offer siblings, the absent routing guidance is the main completeness gap.

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 86%, with per-parameter descriptions for query, category, eligible_as, and the exclusion flags, so the schema does most of the work and baseline 3 applies. The description itself adds no parameter-level meaning beyond the eligibility hint ('who can get each one, what it needs').

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 (find) and a well-scoped resource (free credits, free tiers, trials, eligibility programs), plus the provider domains covered. It lets an agent distinguish this from retrieval-style siblings like get_credit_program or get_offer, though it never explicitly contrasts with search_offers.

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 gives no when-to-use guidance, no exclusions, and does not name an alternative such as search_offers, credits_for_stack, or build_credit_stack. An agent must infer from the name alone whether to call this or a sibling for a given query.

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