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

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds value by explaining what the tool returns (how often analogs led to stress, novelty flag) and its purpose in grounding future prediction in history, which goes beyond the annotation metadata.

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 a single, well-structured sentence that efficiently conveys the core function, the output components, and a usage hint. Every clause adds necessary information with no redundancy or 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?

Given the tool has no parameters, clear annotations, and an output schema (not shown but indicated), the description is complete. It explains what it does, what it returns, and when to use it, covering all necessary aspects for a read-only historical-analog lookup tool.

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 tool has zero parameters, so the baseline is 4. The description implicitly states that it uses 'today's funding conditions' as input context, which clarifies the conceptual basis even though no parameters are exposed in the schema.

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 tool identifies historical days most similar to today's funding conditions and provides stress-event frequency and a novelty flag. It names the specific resource ('historical analogs') and the action (finding nearest analogs), which distinguishes it from siblings like 'funding_stress_now' and 'money_market_context'.

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 explicitly says to use it to ground 'what usually happens from here' questions in real history, providing a clear usage context. It doesn't explicitly list when not to use it or name alternative tools, but the purpose is specific enough that the intended use is unambiguous.

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