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

Annotations establish the mutation profile (readOnlyHint=false, destructiveHint=false), and the description adds real behavioral context beyond that: the place is verified on the map, the creator becomes the first member, and the wording requires their approval. That approval/verification detail is exactly the kind of context annotations can't carry.

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 compact sentences, front-loaded with the action and the triggering condition, then the important side effect. Efficient with no filler, though 'short, warm description' is slightly subjective phrasing for a spec.

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?

An output schema exists, so return values need no explanation, and the description covers the key non-obvious behaviors (map verification, creator becomes first member, wording approval). For a 7-param mutation with well-documented schema, nothing an agent needs 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 description coverage is 86%, so the schema already documents every parameter with examples. The description only loosely gestures at place, schedule and description, adding no format or constraint detail beyond the schema, so 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?

The description gives a specific verb+resource: 'Start a new circle,' and adds concrete qualifiers (real place, schedule, description). It doesn't name the sibling tools (find_circles, join_circle) but the 'when nothing fits' framing implicitly positions it against them.

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?

'Start a new circle when nothing fits' implies the alternative path (find/join an existing circle) but never names it or states the condition explicitly. Usage is implied rather than spelled out, so it is minimum viable.

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