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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds value beyond that: it enumerates the returned fields (tier, category, revenue + basis, pricing model, founded, lessons, growth), the diff with revenue ratio, and a cost/rate limit of 100 calls/day without a key.

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?

Front-loaded with the "Use when..." trigger, followed by return contents, a compact example, and cost. No padding; every clause carries actionable 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?

With an output schema present the description needn't detail return shapes, yet it still summarizes the payload and diff, and it covers triggering, inputs via example, and quota. Nothing an agent needs to invoke it correctly is missing.

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%, so both params are documented as business slugs, and the worked example {"a":"cursor","b":"lovable"} reinforces the expected slug format and which param is which side of the comparison. It adds modest but real meaning over the schema baseline.

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?

States a specific verb (compare) and resource (two AI companies) with the dimensions compared (revenue, business model). It is clearly distinct from siblings like get_business (single lookup) and benchmark_business, so an agent can route without opening schemas.

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?

"Use when the user asks to compare two AI companies (X vs Y) on revenue or business model" gives an explicit trigger condition. It does not name alternatives or exclusions (e.g. what to use for a single company or for non-revenue comparisons), so it stops short of full routing guidance.

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