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

Beyond the readOnlyHint and openWorldHint annotations, it adds useful behavioral context: 15-minute cache freshness, a 30 calls/minute limit, and free cost. It does not cover auth needs or exact caching semantics, but it meaningfully supplements the 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?

Two tight sentences, front-loading the free cached positioning and then the freshness/cost tradeoff. Every clause carries useful selection information.

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 simple, read-only tool with one optional parameter, annotations, and no output schema, the description provides enough operational context about freshness, rate limits, cost, and the alternative. What 'sentiment' actually returns is delegated to the sibling tool rather than explained here.

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 input schema already documents the only parameter, limit, including its 1-7 range and default of 7 at 100% coverage. The description adds no parameter-specific meaning beyond 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?

Identifies the tool as the free cached counterpart to sentiment and distinguishes it from that sibling through refresh cadence, rate limit, and cost. It never explicitly says what the returned sentiment data contains, so it is clear in context but not fully self-contained.

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?

Contrasts this free 15-minute cached copy with sentiment's live per-minute paid data, giving the agent the tradeoff needed to choose between them. There is no explicit 'use when' imperative or stated exclusion, but the alternative and conditions are clear.

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