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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description discloses the resolution order ('crypto registry first, then live stock quote'), the per-leg return fields, the unpriceable fallback ('resolved=false'), and the 'instant' performance trait. This gives the agent a clear behavioral model.

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 sentences carry the full meaning: purpose, context, resolution behavior, return shape, edge case, and safety profile. No filler or redundant restatement of the schema is present.

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 read-only tool with a single array parameter, the description covers the important behaviors the agent needs: validation semantics, resolution order, return fields, and unpriceable handling. The annotations cover safety and idempotency, so nothing critical is 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?

Schema coverage is 100%, so the baseline is a 3. The description adds value by explaining what 'resolve each symbol' means and how price resolution works, supplementing the schema's simple array-of-tickers description.

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 opens with a specific verb phrase, 'Validate and price basket legs BEFORE creating an Event Card,' naming both the action and the resource. It also references the /events/builder page check, making the tool's role immediately distinguishable from the many sibling tools.

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 clearly indicates when to use it: before creating an Event Card, as a pre-flight validation step. It does not explicitly name alternatives or say when not to use it, but the 'same check... runs on every Add' framing provides strong contextual guidance.

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