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

Annotations already declare readOnlyHint=true, and the description confirms 'Read-only.' Beyond that, it adds minimal behavioral context (e.g., no mention of rate limits, pagination, or error handling). The description is adequate but does not significantly enrich behavioral transparency beyond what annotations provide.

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?

Two sentences front-loaded with action and resource, followed by usage guidance and a read-only note. Every sentence adds value with no redundancy.

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 the tool's simplicity (3 parameters, no output schema), the description covers what, when, and safety. It could mention that return format is an array of rows, but that's implicitly understood from 'rows'. Slightly incomplete but largely sufficient.

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%, so baseline is 3. The description mentions the dimension types (segment, geography, etc.) but the schema already defines them via an enum. No additional parameter semantics beyond what the schema provides.

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 verb 'Fetch' and specific resource 'revenue breakdown rows for one exact Bullrun ticker' clearly state the tool's function. It distinguishes from siblings like get_financial_history by focusing on revenue breakdowns and exact ticker-level data.

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?

Explicitly provides use cases: 'separate cyclical businesses from recurring segments or inspect geographic exposure instead of relying on blended revenue.' This gives strong context for when to use, though it lacks explicit when-not-to-use or alternative tools.

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