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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds meaningful context: it returns both inputs and outputs, and establishes the payload's authoritative relationship to signed exports. No contradictions; it complements the annotations without repeating them.

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 what the tool returns. Every phrase earns its place—the detailed enumeration of inputs/outputs and the authoritative context are valuable, with no filler.

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 one-parameter read tool with an output schema, the description is complete. It enumerates the returned content (inputs and outputs) and clarifies the usage context ('every signed export ties back to this payload'), so the agent knows exactly what to expect and why this tool matters.

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 schema has 100% coverage with a clear description for scenario_id. The tool description does not add extra parameter semantics beyond the schema, but it implies the need for scenario_id by saying 'Fetch a PhaseFolio scenario.' This meets the baseline for 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 uses a specific verb ('Fetch') and clearly identifies the resource ('a PhaseFolio scenario's complete inputs... and computed outputs'). It distinguishes this tool from siblings by calling it 'the authoritative engine output' and noting that every signed export ties back to it.

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 provides clear context for when to use this tool—when you need the full scenario payload or the canonical engine result. It does not explicitly name alternatives or state when not to use it, but the authoritative framing guides selection away from other getters.

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