Discover Tools

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

Annotations already cover safety (readOnlyHint true, idempotentHint true, openWorldHint true, destructiveHint false), and the description adds real context beyond them: the ranking dimensions, that unavailable tools are filtered unless include_unavailable=true, what fields come back, and that the call is free. It does not contradict any annotation.

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, front-loaded with the core purpose, followed by return/ranking behavior and cost. Every clause earns its place and nothing is redundant.

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?

An output schema exists, so return values need not be enumerated, and annotations cover the safety profile; the description still supplies ranking, filtering, and cost context. Slightly incomplete only because it omits pagination guidance relative to the limit param, which is minor here.

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 coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: how the filter parameters translate into ordering ('ranked by relevance, then measured quality, then price') and the behavioral effect of include_unavailable. That is genuine semantic value on top of the parameter docs.

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 ('Find callable tools') plus the three filter facets (intent, category, max price) and the ranking order. An agent can tell this is the marketplace entry-point for discovering callable tools without opening the schema, and it is clearly distinct from sibling utility tools like platform.batch.call or account.analytics.tools.

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 implied by the facets ('by intent, category, or max price') but the description never states when to prefer this over alternatives or any exclusions/prerequisites. No sibling tool is named, and the merchant-kind caveat lives only in the schema. Adequate but leaves routing to inference.

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