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

Annotations already carry the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description still adds real value: the summary is 'built without AI, the same text the Baselines tab shows' (deterministic, reproducible output), duration variance uses the stored planned duration rather than the date span, and availability is stated.

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?

Front-loaded with the tool's purpose and result shape in the first sentence, and the routing hint and availability note come last. It is dense and long, but with no output schema the field enumeration earns its space; only the double-length first sentence could be tightened.

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 no output schema and one undocumented parameter, the description does the compensating work: it enumerates every returned field and describes the summary contents down to the 'five largest start or finish moves'. An agent can reason about the result without inferring anything.

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 50%: maxTasks is documented and baselineId is not. The description implies baselineId scope ('one of its baselines') and confirms the 'worst slippers' meaning of maxTasks, but adds no format or ID-source detail. Baseline 3 is right given partial schema coverage.

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 (computed variance) and resource (project against one of its baselines) and enumerates the exact outputs: finish slip in calendar days, RAG rating, task counts, worst slippers. It explicitly distinguishes itself from get_baseline, so an agent can route without opening either 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?

Names the alternative get_baseline and the condition for choosing it ('for the raw snapshot'), and notes availability ('Available on every plan'), which rules out plan-gating surprises. It stops short of an explicit when-not or prerequisite statement, so it lands just below the top band.

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