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

With annotations already indicating readOnly and non-destructive, the description adds substantial value: billing details (per-platform credits, no charge on platform failure, charge even on empty AI answer), slow execution, and truncated output. 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?

Information is front-loaded with the core action, then cost, then return values. Slightly dense with three topics in one block, but each sentence carries distinct, useful information and nothing is redundant.

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?

Covers the essential operational context: platforms, slowness, credit behavior, truncation, and return payload. No output schema exists, so the description adequately fills that gap. Minor omission: the confirm_quote_id two-step flow is left entirely to the schema, and platform-specific availability isn't mentioned.

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 covers all 5 parameters with descriptions (100% coverage), so the baseline applies. The tool description adds general context (cost per platform) but no parameter-specific elaboration beyond what the schema already states.

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?

Description uses a specific verb ('Runs a prompt live') and explicitly names the platforms (Google AI Overview, Google AI Mode, ChatGPT, Gemini) plus the key return value (whether the domain is cited). This makes the tool's purpose unambiguous and distinguishes it from generic search tools.

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 clear operational context: cost per platform, slow runtime (up to 90 seconds), and truncation behavior. Does not explicitly state when to choose this over sibling tools like ai_overview or ai_compare, but the cost and latency warnings give a strong practical usage signal.

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