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

Annotations already declare readOnly/idempotent/closed-world, but the description adds real value: pure arithmetic with no I/O or external calls, results rounded to 2 decimals, parameters of non-selected methods silently accepted and ignored, and an explicit error contract for unknown methods or missing required method params. It does not, however, describe output shape in detail (though an output schema exists).

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?

Dense but front-loaded: purpose, then routing to siblings, then per-method parameter requirements, then behavioral/error notes. Every sentence carries information, though the block is longer than strictly necessary for a single calculator tool.

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?

All seven parameters are documented in the schema, an output schema exists so return values need no prose, and the description supplies the method-to-parameter mapping plus error and rounding behavior. An agent has everything needed to invoke either branch correctly.

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% for individual fields, yet the description adds cross-parameter semantics the schema cannot express: which parameters belong to which method (cup_transfer_price needs controlled_price + uncontrolled_prices; patent_infringement_damages needs lost_profits_or_royalty + infringement_period + discount_rate + prejudgment_interest_rate), and the constraint that uncontrolled_prices must contain at least one comparable.

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?

States a specific computation (Comparable Uncontrolled Price arm's-length range and patent infringement damages with pre-judgment interest) and explicitly scopes it to OECD intercompany-intangible pricing and patent damages. It also names the sibling tools it is NOT (valuation_royalty_analysis, valuation_ip, valuation_income_methods), so an agent can route without opening schemas.

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?

Gives explicit when-to-use cases ('OECD transfer-pricing pricing of intercompany intangibles', 'patent infringement damages awards') and names the correct alternatives for adjacent tasks (royalty-rate benchmarking, substantive asset valuation). Method selection is also described per branch, leaving nothing to inference.

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