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

Annotations already establish readOnlyHint, idempotentHint, and non-destructive behavior. The description adds meaningful context beyond them by emphasizing that calculations are strictly deterministic and mathematical, and that the tool offers no trading or predictive signals. This helps an agent calibrate expectations. No contradiction with annotations.

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?

Front-loaded with a clear one-sentence purpose, followed by bulletized parameter specifics and a concise list of return fields. It is slightly detailed but every section earns its place; no filler or tautological content.

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 three-parameter surface and availability of an output schema, the description covers everything needed for an agent to call the tool correctly: required parameter, conditional formats, defaults, output metrics, and behavioral limits. There are no significant missing invocation details.

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 the baseline is 3. The description goes further by providing concrete examples, conditional date formats for each targetType, and clarifying default behavior (latest event, EURUSD instrument). This adds real value beyond the schema field descriptions.

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 'Retrieve' and a specific resource: deterministic post-event market reaction metrics for economic releases or monetary policy statements. It identifies the distinct output (standardized windows and metrics) which separates it from context/analog tools, though it does not explicitly name a sibling alternative.

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?

Parameter usage is clearly specified: targetType is required, dateOrPeriod has conditional formats per targetType, and instrument has a default. It also sets expectations by stating it does not provide recommendations or predictions. However, it does not explicitly say when to choose this tool over siblings like get_historical_reaction_context or get_event_context.

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