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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the agent knows the safety profile. The description adds valuable context: it's a self-aggregating signal from CF analytics-engine with no PII, and caching behavior varies by window (5min–1h). This goes beyond annotations but doesn't cover rate limits or failure modes, so a 4 is appropriate.

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 moderately sized but every sentence contributes: purpose, return value, use cases, data source, privacy, and caching. It's front-loaded with the main purpose and structured nicely. Not overly verbose, though it could be trimmed slightly without losing critical information.

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 no output schema, the description adequately summarizes the return content (top tools, packs, total call volume). For a simple tool with one optional parameter, it covers the key aspects: what it does, when to use, data source, privacy, and freshness. It doesn't detail the exact response shape or error handling, but that's acceptable for this complexity level.

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% for the only parameter 'window', with an enum and default value described. The description adds semantic meaning by explaining the trade-off between shorter and longer windows ('hot right now' vs 'steady-state demand'), which is not fully present in the schema. This enhances the parameter's meaning beyond the schema alone.

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 'Returns the top tools, top packs, and total call volume' over a recent window, using a specific verb and resource. It distinguishes itself from siblings like 'discover_tools' by focusing on aggregate trending activity rather than individual tool discovery, making its purpose unmistakable.

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 lists three 'Useful for' scenarios (discovering hot data sources, confirming canonical choices, aligning use cases) and provides window-selection guidance ('shorter windows surface what's hot; longer windows show steady-state'). It doesn't explicitly mention when not to use or alternative tools, but the context is clear enough to guide an agent.

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