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

With no annotations provided, the description carries the full burden. It discloses key behaviors such as deltas against the baseline, optional ranking with 'goal' (max/min), and include_projections for per-period series. This goes beyond a simple 'compares scenarios' and provides actionable behavioral detail, though it omits some edge-case behaviors like error handling.

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 two sentences, with the primary purpose front-loaded and additional usage details compactly integrated. Every phrase earns its place, using quoted parameter names for clarity. There is no unnecessary repetition or fluff.

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?

The tool has no output schema, but the description at least mentions key_results and per-period series, giving the agent an idea of the return shape. The scenarios array and optional ranking are well covered. It's not exhaustive (e.g., no mention of units or exact response structure), but for the tool's complexity, it is sufficiently complete 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?

Schema coverage is 100%, so baseline is 3. The description adds value by explaining the relationship between per-scenario and top-level 'horizon', the structure of the scenarios array (including custom 'metrics'), and the effect of include_projections. This exceeds what the schema's descriptions alone provide, justifying a 4.

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 action ('Run 2-3 scenarios and compare their key_results side by side') and specifies the resource (scenarios) with the key differentiator of deltas against the baseline. This distinguishes it from sibling tools like run_scenario, which runs a single scenario.

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?

It implies when to use (comparing 2-3 scenarios) and provides explicit structural guidance on the 'scenarios' array, top-level 'horizon', and optional ranking. It doesn't explicitly list alternatives to avoid, but the context of comparing multiple scenarios is clear. A 4 is appropriate for clear context without explicit exclusions.

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