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

Even with readOnlyHint=true and destructiveHint=false, the description adds significant behavioral context: it discloses self-aggregation, derivation from CF analytics-engine, no PII, and caching windows (5min-1h). This goes well beyond what annotations provide, giving the agent a clear model of what the tool does and its side effects (none).

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 well-structured: a core statement, a bulleted 'Useful for' section, and a concise data/caching note. It is slightly longer than necessary, but every sentence adds value and the most important information is front-loaded.

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?

For a simple read-only tool with one optional parameter and no output schema, the description is complete. It covers what is returned (top tools, top packs, total call volume), the data format ('just (pack, tool, count)'), privacy (no PII), caching, and usage context. No gaps for an agent to invoke it correctly.

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?

The single parameter 'window' is fully documented in the schema with enum values and a meaningful description ('Shorter windows surface what's hot right now; longer windows show steady-state demand'). The tool description only mentions the window in passing ('24h, 7d, or 30d') and adds no new parameter semantics, so the baseline of 3 applies given high schema coverage.

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 explicitly states the function: 'Returns the top tools, top packs, and total call volume over a recent window', with a clear verb and resource. It also distinguishes itself from siblings by framing the data as a self-aggregating signal from other AI agents, not just a generic discovery tool.

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 a clear 'Useful for' list with three specific scenarios (discovering hot data sources, confirming canonical tools, aligning use cases) which gives explicit context for when to use it. However, it does not mention when not to use it or explicitly name alternative tools, so it falls short of a 5.

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