Daily Performance Report

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds behavioral context beyond annotations by specifying the exact time ranges and alert behavior, and reiterates the pure-read nature, which aligns with and reinforces the 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 extremely concise: two sentences that cover purpose, key functionality (time periods, alert), and read-only nature. Every sentence adds value with no redundancy or fluff.

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?

Despite having an output schema (not shown), the description adequately covers the tool's core functionality and key parameters. For a report tool that aggregates data, the description is sufficiently complete with no obvious gaps.

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% (all four parameters have descriptions). The description does not add significant new meaning beyond what the schema already provides; it only mentions the alert threshold briefly. Baseline score of 3 is appropriate.

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 it is a synthetic daily performance snapshot pulling YESTERDAY, LAST_7_DAYS, and LAST_30_DAYS aggregates, with optional CPC alert. It explicitly distinguishes itself as a read-only aggregate, differentiating from sibling tools like get_account_performance or get_campaign_performance that focus on specific entities.

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 provides clear context on the tool's output (time-based aggregates, optional alert) but lacks explicit guidance on when to use this tool over alternatives or when not to use it. No 'when-not-to-use' or sibling comparisons are mentioned.

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