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

With no annotations provided, the description carries the full transparency burden and excels: it discloses server-side URL reading, the semantic signal used (title, headings, copy), and explicitly notes the limitation that pixel-level palette/type extraction is not yet supported (Phase 2 vision pass). This is rich, honest behavioral disclosure.

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?

The description is compact yet information-dense, front-loaded with a memorable hook ('show me what you like, I'll build it') and then logically covering inputs, process, outputs, and a limitation. Every sentence adds value, and no space is wasted on repetition of schema details.

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 tool with 8 parameters, no output schema, and no annotations, the description is remarkably complete: it explains what the tool returns (direction, build plan, next call), how the reference is processed, what is not supported, and how to anchor on exact references. This gives an agent sufficient context to select and invoke the tool correctly.

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 100%, so a baseline of 3 applies, but the description adds meaningful semantics beyond the schema: it clarifies that 'business' means what you are building (not the reference), that reference_id comes from search_references, and how reference_url is used server-side. This contextual glue improves parameter comprehension beyond the property descriptions.

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 opens with a clear verb+resource: 'build' from a reference, and explicitly frames it as the 'front door for building from an EXAMPLE instead of a text brief.' It distinguishes itself from text-based builds and lists concrete outputs (direction, build plan, next call), making its purpose unmistakable even among siblings.

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 states when to use it: when you have a reference example rather than a text brief, and gives guidance on choosing between reference_url and reference_id. It also tells users to pass reference_id to anchor on an exact curated reference, providing clear context though not explicitly naming alternatives like build_from_reference_v2.

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