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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds substantial context beyond that: it explains the return shape (ranked panel, one per product, image_url, pixel-measured spec, core design tokens) and the no-match fallback behavior (returns available section types).

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 purpose, then a usage trigger, then a clean Args block. Every sentence earns its place, though the argument examples are somewhat verbose given the schema exists.

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, and the description compensates by describing the return payload and the no-match fallback. For a read-only comparison tool with fully documented params, nothing needed for correct invocation is missing.

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 0%, so the description must carry the full burden — and it does. Each of the 4 parameters gets meaning beyond the schema: enumerated section_type values, industry examples, scheme semantics ('matches the section's measured background'), and the limit range (1-12, default 8).

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 (compare), resource (sections), and distinctive scope: 'how the BEST products each solve the same section — one call, cross-product.' This differentiates it from siblings like compare_components and compare_recipes without opening their 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?

'Use before designing any section' gives explicit timing context and a concrete invocation example. It does not, however, name alternatives (e.g., when to prefer compare_components or get_section), so it stops short of the when-not/alternative bar.

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