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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds context: 'read-only, idempotent over the same window', source tables (AIToolCallLog, ValueEvent, AIValidationRunLog), and special behavior for private_session bypassing logging. No contradiction with annotations.

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 structured with sections (first sentence, returned fields, WHEN TO CALL, WHEN NOT TO CALL, BEHAVIOR) and front-loaded with the main purpose. It is slightly long but every sentence adds value. Minor redundancy with annotations is acceptable.

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 the tool's complexity (aggregation from multiple sources, two parameters, annotations, output schema), the description is thorough. It explains what is returned, source tables, logging behavior, and auth/plan restrictions. Output schema exists, so no need to detail return format.

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% with clear parameter descriptions. The description adds value beyond schema by stating the default window (30 days) and explaining that private_session only affects logging of the read, not underlying data.

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 that the tool summarizes the caller's tool-usage patterns and value signals over a configurable window, listing specific return fields. It distinguishes from siblings by noting it returns only the caller's own data, which differentiates it from tools that might compare users or provide broader analytics.

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?

Provides explicit WHEN TO CALL with example user queries (e.g., 'how is the Blueprint helping me/my team') and WHEN NOT TO CALL (proactively, on every turn, to compare users). Also mentions auth and plan requirements. This is comprehensive guidance.

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