Explain one Barometer indicator

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the shape of the returned explanation, which the output schema already carries, and says nothing about rate limits, lookup failure behavior for unknown keys, or freshness of 'current value'.

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?

A single front-loaded sentence that lists the three outputs in priority order with no filler. It is a sentence fragment rather than a complete statement, which costs it the top mark, but nothing needs trimming.

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?

The tool is simple: one required enum parameter, full schema coverage, and an output schema that carries return-value detail, so the description need not explain the response. The description covers the core purpose adequately; only explicit sibling routing and failure behavior for an invalid indicator key are missing.

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?

There is a single parameter with 100% schema description coverage and a 10-value enum, so the schema already tells the agent exactly what to pass. The description adds no meaning about the 'name' key beyond what the enum and its 'Indicator key' description provide; baseline 3 applies when the schema does the heavy lifting.

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 states a specific verb (explain) and resource (one Barometer indicator) and enumerates the three things it returns: what the indicator measures, its current value/heat, and its contribution to the score. That is enough to distinguish it from get_history and get_market_snapshot, though it never explicitly names those siblings.

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?

Usage is implied by the phrasing 'how it feeds the score' — an agent would call this when it needs to understand a single indicator or justify a score contribution. However, there is no explicit when-to-use, no when-not-to-use, and no mention of the sibling tools that might otherwise be reached for.

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