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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds the critical specifics beyond that: it overwrites only the recipe matching the same coffee/grinder/machine/program/drink-intent tuple, and preserves the existing recipe_id. That explains exactly what is destroyed and how identity is retained, which the annotations alone cannot convey.

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?

Two sentences, no filler, and the definition of the action is front-loaded before the overwrite rule. Every clause earns its place.

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?

With an output schema present, the description needn't explain return values, and the annotations cover the safety profile. It covers the mutation effect well; only minor gaps remain, such as failure behavior or why drink_intent (straight/milk) is a required selector.

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?

With 0% schema coverage the description must carry the load, and it does: it frames from_shot_id as the 'successful shot' source and names the composite key (coffee, grinder, machine, program, drink intent) that determines which record drink_intent selects. This meaningfully exceeds the bare enum/integer schema, though from_shot_id's exact semantics remain only implied.

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 (lock) and resource (recipe) and defines what locking means: promoting a successful shot to the reference dialing recipe for the equipment profile. This clearly separates it from list_recipes, update_shot, or log_shot.

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?

The phrase 'Lock a successful shot' implies you should have a successful shot to promote, which is implied usage context. However, it never states when-not to use it or points to any alternative (e.g., list_recipes or update_shot), leaving the routing to inference.

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