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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description still adds genuinely non-obvious behavior: results change conditionally depending on whether the five lifestyle answers are supplied (easier-to-find breeds at least 10 points better fit, with fit %, versus look-and-vibe twins), plus a note that a visual widget card may already be shown. That conditional-logic disclosure is valuable, though it doesn't cover result count or ranking ties.

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 dense but front-loaded: trigger, mechanism, conditional behavior, alternatives, UI guidance, and exclusions each occupy one clause with no repetition. It is longer than average, but each sentence carries distinct routing or behavioral information, so little is wasted.

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?

There is no output schema, and the description partially compensates by stating what comes back (breeds with their fit %) and how the widget card interacts with the text reply. Combined with a 6-parameter schema and rich annotations, an agent has enough to call it correctly, though number of results returned and ranking behavior remain unstated.

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% with enums documented, so the baseline is 3. The description adds meaning the schema cannot: the five optional lifestyle parameters are not just filters but a mode switch that changes the entire result set and gates the fit-% output. It doesn't describe per-parameter validation (e.g. breed string matching), so it stops short of 5.

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 ('finds breeds that share the look and personality of a breed the user is drawn to') with concrete examples of the user's phrasing. It explicitly contrasts itself against match_dog_breeds and assess_breed_fit, so an agent can distinguish it from the closest siblings without opening a 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?

Gives explicit trigger conditions ('user loves a breed that may not fit them', 'something similar but easier'), names the two alternatives and the condition that selects each, and adds hard exclusions (no symptoms/emergencies/treatment, no training how-tos). This is full when/when-not/alternative coverage.

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