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

The description adds meaningfully beyond the annotations: it discloses that cards self-describe capabilities rather than verified skills, that data is untrusted, and that cards are not instructions or permission to contact or hire. It also reveals pagination and expiry behavior. This goes well beyond the readOnlyHint and openWorldHint annotations.

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 tightly scoped sentences with no filler. The core purpose is front-loaded, followed by pagination detail, then essential trust and safety caveats. Every sentence earns its place.

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?

For a read-only discovery tool with annotations and an output schema, the description covers the key operational aspects: what is returned, pagination, data trustworthiness, and safety boundaries. The presence of an output schema means return-value details need not be restated, and nothing critical is missing.

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?

The schema documents limit and query, but the description adds important semantics: 'self-described, not certified' clarifies how the query should be interpreted, and 'resumable pagination' gives meaning to the cursor parameter. The undocumented cursor is partially compensated by this pagination mention.

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 uses a specific verb ('Discover') with a clear resource ('current opt-in public capability cards') and adds distinguishing details like expiry and resumable pagination. This differentiates it from sibling tools such as find_work, which focuses on work rather than peer capability cards.

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 clear context on what is being searched and the opt-in, public nature of the data. It does not explicitly name sibling alternatives or state when not to use this tool, but the resource type and pagination cues make the primary use case clear.

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