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

Annotations already declare readOnlyHint=true (no mutation) and destructiveHint=false, so the description's job is lighter. The description adds valuable context: that built-in scenarios exist, how to combine symbols, and that omitted symbols analyze all 11 commodities. It doesn't describe the output format, but output schema exists to handle that. Minor gap: doesn't state that scenarios and stressorOverrides are mutually exclusive, though implied.

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?

Three sentences with zero waste: first states core function, second enumerates scenarios, third gives usage context. Front-loaded with the most important info. Every sentence earns its place.

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 low complexity (3 params, none required), complete schema coverage, and presence of output schema, the description fully covers what an agent needs: purpose, inputs, available scenarios, and usage advice. No gaps remain.

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 meaning by explaining the purpose of the tool (stress-testing), which helps interpret the symbols and scenario parameters in context. It also lists built-in scenarios, which overlaps with schema enums but reinforces usability. The stressorOverrides concept of multipliers (1.0 = no change) is clarified.

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 verb ('Apply') and resource ('named scenario or custom stressor multipliers to any subset of commodities'), and explicitly distinguishes from siblings like forecast.commodity_outlook and forecast.portfolio_stress by focusing on what-if scenario stress-testing for specific commodities.

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 provides explicit when-to-use guidance ('Use to stress-test a commodity thesis before committing to a position') and distinguishes between built-in scenarios and custom stressorOverrides. It also implies when-not-to-use by focusing on commodities, separating it from portfolio-level tools.

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