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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real behavioral context beyond that: it discloses graceful degradation (curated catalog recipe 'when available, or a roast-based starting point') and that brew-method scoping is optional. It does not say what happens with an unrecognized coffee or what the returned recipe shape looks like.

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?

One compact sentence, front-loaded with the core purpose followed by a colon that enumerates the returned fields, then the fallback and the optional scoping. Every clause carries information; nothing is padding.

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 two-parameter, read-only tool with no output schema, the description tells the agent what it gets back (ratio, temperature, grind) and what happens when no curated recipe exists. Only the exact response shape/format is left unspecified, a minor gap.

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%, so both parameters are already documented ('Coffee id or name', 'Your brewer, e.g. V60'). The description adds only the mild nuance that brew_method is optional and scopes the guidance, which does not go beyond what the schema conveys; baseline 3 applies.

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+resource: it returns brew guidance (recipe: ratio, temperature, grind) for one coffee. An agent can distinguish it from list-style siblings like search_coffees or trending_coffees, though it never explicitly contrasts itself with what_to_brew, the closest sibling.

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: 'for a specific coffee' and 'optionally scoped to your brew method' suggest when it applies, and the fallback clause hints at reliability, but there is no explicit when-to-use vs. what_to_brew / get_recommendations guidance.

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