search_capabilities

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

With no annotations, the description carries the full burden and does well: it discloses the return shape (slug, service, side-effect class, readiness, description, params schema-on-hit), the origin-biasing behavior, and the critical execution gate that "only t1-ready hits are direct API executable." It stops short of stating auth requirements or whether the search itself has side effects, leaving minor gaps.

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?

Front-loaded with the core purpose, then supporting detail in a logical order. It is dense but every clause is informative (return fields, readiness gate, origin bias); a slightly tighter phrasing of the return-field list would improve it.

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 search tool with no output schema and no annotations, the description covers the return contract, ranking limit, and execution-readiness semantics well. It omits what "FSB" scope entails and any auth or rate considerations, but nothing essential to calling it correctly 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?

Schema description coverage is 100%, so all four parameters are already documented in the schema, and the baseline is 3. The description reinforces topN ranking and origin biasing ("Results are biased toward the resolved tab origin") but adds no syntax or semantics beyond what the schema already provides.

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 FSB capability catalog") scoped by "intent", and positions itself relative to siblings by telling the agent to use it "before DOM tools for first-party actions on the current site." An agent can distinguish this discovery step from the DOM-interaction tools and from the sibling invoke_capability executor without opening the schema.

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 explicit when-to-use context ("before DOM tools for first-party actions on the current site") and a positive trigger. It does not state when-not to use it, nor does it name invoke_capability as the follow-on execution step, so routing is clear but not fully closed.

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