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

With no annotations, the description carries the full burden and does well: it discloses the UI side effect (renders a carousel), states the no-results policy, forbids automatic follow-up calls into detail tools, and caps the call-count pattern per category. It does not mention auth/session prerequisites or whether the carousel replaces or appends to prior output, which keeps it from a 5.

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 and the most important constraint (faithful query), then rules in priority order. A few directives overlap — "do not repeat or rephrase" is restated by the later synonyms/colours/styles sentence — so the text could shed roughly a sentence without losing meaning.

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?

Output schema exists, so return values need no explanation, and the description supplies the decision rules a 6-parameter search tool needs. The only remaining hole is buyer_context, which is undocumented in both schema and prose and could matter for personalized results.

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?

Adds real meaning beyond the 83%-covered schema: query must be the shopper's wording passed through unrewritten, and min_price/max_price are in major currency units with the non-obvious rule that using both with the same value means an exact price. Only buyer_context is left undocumented in both schema and description.

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?

Opens with a specific verb and resource ("Search Trailberg and render the interactive product carousel") and immediately distinguishes itself from the closest sibling by naming render_complete_the_look for pair/match requests. An agent can route correctly without opening any other schema.

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?

Explicit when-to-use (browsing/discovery, single requested concept, multiple explicit categories), when-not-to-use (not a preliminary lookup for an exact product-detail request), what to do on empty results (show empty result, ask before retrying), and which alternative to pick (render_complete_the_look, product-detail tools). This is close to exhaustive routing guidance.

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