gap_scan

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

Annotations already cover read-only, idempotent, and non-destructive; the description adds genuine behavioral value by revealing the quiet digest mode and the actionable:false no-op contract. That sort of runtime behavior goes beyond what readOnlyHint and idempotentHint can convey, so it earns credit.

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 with no wasted words: the first states exactly what the tool scans for, the second instructs the scheduler how to call it and interpret the result. It is front-loaded and every phrase 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, idempotent scan with hand-documented parameters, the description plus schema is sufficient to invoke the main flow correctly. The only gap is the full shape of an actionable=true report — no output schema exists—but the description does enough to make the tool safely callable.

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%, and each parameter already explains itself: digest_only describes a hands-off quiet mode, reference_systems gives its registry fallback behavior, and use_cases defines the coverage term source. With full schema coverage the described baseline of 3 is correct.

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 states a specific verb ('Scan') and a specific resource ('the local Decision Graph'), then itemizes exactly what is detected: uncovered components, weak rationales, contested decisions, and derived staleness. This level of detail, along with the unique resource, cleanly separates it from sibling scan/audit tools like talon_scan.

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?

It gives explicit guidance to its main caller class ('Schedulers should call with digest_only:true') and clarifies the expected result ('treat actionable:false as a no-op'). It does not name alternates or state when this tool should not be used, but the intended invocation context is clear.

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