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

Annotations already declare readOnly=true, destructive=false, openWorld=false, so the safety profile is covered. The description adds real behavioral context beyond that: it caps output at 30 forms, guarantees no field values are returned, confirms nothing is submitted, and notes free/no-key billing plus 'existing source and input limits apply.'

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 action, then constraints. Four short sentences, though the pithy 'FREE during validation. No key, credits or wallet.' fragments are slightly telegraphic rather than flowing prose.

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?

An output schema exists, so return-value shape need not be described. Combined with annotations covering safety and the description covering scope, limits, and billing, the definition gives an agent enough to call it correctly, with only parameter intent left underspecified.

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 coverage is only 67% and the description never mentions the html or baseUrl inputs, leaving their intent to the schema. It does contextualize the legacy requestId and maxPriceMicroUsd fields via 'No key, credits or wallet,' but this is thin for a nested-object schema.

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 ('Describe up to 30 forms and their controls') and scopes the output with 'without returning field values or submitting anything.' The 'forms' resource distinguishes it from sibling html_* tools like html_tables and html_links without needing to name them explicitly.

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?

Usage is only implied: an agent infers it should call this to understand form structure in HTML. There is no explicit when-to-use, no exclusion condition, and no named alternative among the html_* siblings, though the cost notes ('FREE during validation') hint at a context.

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