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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered without the description. The description adds two useful behavioral facts: the algorithm used (interval scheduling) and a per-call cost of 1 credit, which annotations cannot convey; however it says nothing about the shape of the result or error behavior for malformed intervals.

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 short sentences, front-loaded with the purpose, followed by the algorithm and cost note. Nothing is padded, though the algorithm sentence is arguably optional garnish.

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 single-parameter, no-output-schema computation tool this covers the essentials (what it computes and honest naming), but it stops short of stating that the return value is a single integer count and does not clarify the interval input encoding that the schema leaves ambiguous.

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 the baseline is 3. The description restates that intervals are supplied but adds no format detail, and it does not resolve the schema's ambiguity where the parameter is typed as an array of strings or a plain string while the schema text describes an array of arrays.

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 and resource ('Finds the minimum number of meeting rooms required') plus the computation's premise ('given their time intervals'), which is unambiguous. It does not differentiate from the nearby sibling can_attend_meetings, so an agent must infer the boundary itself.

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 implied by the problem framing (supply meeting intervals, get the minimum room count), but there is no explicit when-to-use versus when-not, no mention of can_attend_meetings as an alternative, and no prerequisite guidance. Adequate but leaves the routing decision to the agent.

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