Market Scenario Simulator

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

Annotations already declare readOnlyHint=true and idempotentHint=true; the description adds substantial context beyond that: what the response contains (baseline vs scenario composite, component breakdown, exact formula/weights), that the composite is deliberately NOT the DCPI, and keyless vs keyed caller differences (top-3 preview vs up to 25). These behaviors are not visible in annotations or schema, and no contradiction exists.

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 compact given the tool's complexity. Every sentence contributes: purpose, parameter semantics, return structure, keyless limitations, example call, and exclusions. It is front-loaded with the core purpose and ends with a crisp example and alternative routing. No redundant or filler content exists.

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 counterfactual simulation tool with 7 optional parameters and an output schema, the description covers all essential context: what it computes, how to invoke it, what the response contains, auth/key behavior, parameter constraints, an example, and when not to use it. The existing output schema covers return details, so the description is appropriately comprehensive.

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 adds value beyond the schema by explaining the overall parameter contract ('all optional, pass at least one delta'), giving a concrete invocation example ('simulate_scenario avg_kwh_cents_pct=30 top_n=10'), clarifying units (points vs months) with examples, and defining ranking semantics ('ranked by |score change|'). This earns an above-baseline score.

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 opens with a specific verb and resource: 'Counterfactual WHAT-IF re-scoring of 300+ DC Hub power markets under YOUR explicit deltas' and phrases the core question it answers ('what happens to the market ranking if conditions change'). It clearly distinguishes this from present-day ranking (rank_markets) and trajectory extrapolation (predict_market_trajectory), making the tool's unique role 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 gives explicit when-to-use guidance ('explicit hypotheticals'), warns against using it for present-day ranking and trajectory extrapolation by naming the exact sibling tools to use instead, and states the requirement to 'pass at least one delta' even though all params are optional. This leaves no ambiguity about when to invoke this tool versus alternatives.

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