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

Annotations already include readOnlyHint=true, and the description does not contradict it. The description adds valuable context on return values ('score (0-100), verdict, per-layer year/month/day breakdown, etc.'), which goes beyond the annotations. No destructive or auth information is needed as it's a read operation.

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?

The description is a single paragraph of about 5 sentences, front-loaded with the primary use case. Every sentence adds value without redundancy. It is concise and well-structured.

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?

Given there is no output schema, the description adequately explains return values (score, verdict, breakdowns). It covers the three modes and references sibling tools. Could mention that output is JSON, but otherwise it is complete for a tool of this complexity.

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 coverage is 100% with all parameters described, so baseline is 3. The description adds extra meaning by explaining modes (e.g., 'Modes: single date, compare up to 5 dates, or scan a range up to 31 days'), constraints (max 31 days for range, max 4 compare dates), and the optional nature of birthInfo. This adds significant value beyond the schema.

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 clearly states the tool's purpose: 'Call when the user asks about timing a decision for a specific date, or wants to pick the best day from a multi-day window.' It uses specific verbs and resources, and distinguishes from sibling tools by mentioning alternatives for longer windows or hour precision.

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 description explicitly states when to use the tool, provides examples of scenarios (trip dates, launch days, etc.), mentions modes (single date, compare up to 5 dates, scan range up to 31 days), and gives exclusion criteria: 'For multi-month windows use intentions_ask_month; for hour precision use intentions_ask_hour.'

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