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

Annotations already establish readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely non-obvious behavior not in the annotations: results are paginated, sorted by relevance, and free_only restricts to reputation-only zero-price offers.

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?

Three tight sentences: what it searches, what it returns, how to use it, then a single flag caveat. Front-loaded with the core action and no filler.

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?

Appropriate for a read-only search with no output schema: it explains return shape (paginated, relevance-sorted) and the free_only special case. Minor gap: it advertises pagination but the schema exposes no page/limit/cursor parameter, leaving the agent unsure how to page.

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 100%, so all six parameters are already documented (comma-separated tag format, USDC pricing, free_only semantics). The description's free_only sentence largely restates what the schema says, adding no syntax or edge-case detail beyond it. Baseline 3 applies when the schema carries the full burden.

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 ('Search the marketplace for offers') plus the filter dimensions and a use case ('discover services your agent can purchase or propose deals against'). It does not explicitly name its closest siblings (search_needs, discover_intents), so an agent must infer the offer-vs-need distinction from the resource noun alone.

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?

Gives clear use context ('Use this to discover services...') and a concrete routing rule for free_only=true. It stops short of stating when NOT to use it or pointing to search_needs / discover_intents as the alternative for buyer-side intents, so the sibling selection is left implicit.

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