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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely non-obvious behavior: a fixed 0.01 USDC x402 charge on Base per call and the X-Provider-Key header requirement for customer-owned credentials — cost and auth context the annotations cannot express.

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, front-loaded with what is computed and followed by the cost/auth constraints. Every clause carries information the agent needs and there is no 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?

The tool is a multi-input computation with no output schema, yet the description never indicates what comes back (per-ingredient cost breakdown, total batch cost, gross margin figure). Payment and auth are covered, but the result shape is left entirely to inference for a 4-parameter compute operation.

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 nominally 100%, but every property description is boilerplate that defers to the operation description, so the schema adds little real meaning. The description compensates only for 'ingredients' (the colon-delimited herb:grams:price_per_gram format) and leaves batches, packaging_per_batch, and selling_price_per_batch units/currency unexplained. Baseline 3 fits.

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 names a specific verb and resource: computing actual retail herb blend batch ingredient costs and gross margin. That is far more precise than the bare tool name and separates it in spirit from the herb siblings (formula_scale, lot_fefo, reorder, traceability), though it never names an alternative explicitly.

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 input format 'herb:grams:price_per_gram' and by the stated preconditions (0.01 USDC payment, optional X-Provider-Key), which tells an agent how the call is paid for and authenticated. However, there is no when-to-use vs. when-not guidance and no routing to the four sibling herb tools, so the agent must infer which one applies.

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