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

readOnlyHint=true already tells the agent this is a safe non-mutating operation, so the bar is lower. The description still adds real context: the specific platform invariants enforced and the return shape (severity plus per-violation keys), which annotations cannot convey.

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, front-loaded with the validated invariants and followed by usage and return info. The parenthetical invariant list is long but each item earns its place by telling the agent what will be flagged.

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?

No output schema exists, yet the description discloses the return shape (severity, per-violation keys), and the read-only annotation covers the safety profile. For a single-parameter validation tool this is nearly complete, with only the exact violation vocabulary left unspecified.

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 the single content parameter is already documented as the full workflow YAML. The description adds no syntax or format guidance beyond what the schema provides, so the baseline 3 applies.

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 (Validate) and resource (a GitHub Actions workflow YAML string), then enumerates the exact invariants checked (single build-and-push job, step sequence, --password-stdin, lowercased GHCR owner, etc.). This clearly distinguishes it from siblings like cicd_validate_pipeline_yaml and validate_cluster_manifest, which target different artifacts.

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?

"Use this to inspect a customer's pre-existing workflow before splicing security steps" gives a concrete usage context and implies the workflow stage it belongs to. It does not, however, explicitly name alternatives such as cicd_convert_workflow_to_pipeline or state when NOT to use it, so routing rests partly on inference.

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