validate_markup

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds meaningful scope beyond that: it is a static (non-executing) check and it names the specific failure classes it detects plus the diagnostic output containing errors/warnings. It stops short of describing result structure, but with no output schema this is a minor gap.

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-loads the stage tag and alias relationship before the check scope, then closes with the next step. Dense but every clause carries information; the enumerated check list is long but relevant. No redundant filler.

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 4-parameter, zero-required validation tool with no output schema, the description covers purpose, scope of checks, workflow stage, and the follow-up action, and hints at the diagnostic return. What an agent needs to call it correctly is essentially present; only explicit return-shape or required-parameter guidance is absent.

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 (code, html alias, densityProfile, semanticProfile) are already documented in the schema, including the alias relationship and enum. The description adds no additional parameter-level syntax or format detail, which matches the baseline 3 when the schema does the heavy lifting.

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 (statically check) and resource (HTML/Astro source), then enumerates exactly what it inspects: Basecoat migration errors, semantic rhythm, FSM bindings, missing scripts, nested cards, spacing and hierarchy. It also declares itself 'Alias of validate_composition' and tags '[STAGE 4: QUALITY AUDIT]', so an agent can place it against siblings without opening schemas.

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 pipeline context via the '[STAGE 4: QUALITY AUDIT]' tag and a clear next step ('Fix any errors/warnings reported in the diagnostic output'). It also identifies itself as an alias of validate_composition, implying interchangeability. It does not, however, explicitly state when to prefer this alias over validate_composition or when validation is unnecessary.

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