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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds substantial context beyond them: pure arithmetic with no I/O or external calls, 2-decimal rounding, rate format as decimals, method-dependent parameter handling, and explicit error behavior for unknown methods or missing required params.

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?

Front-loads purpose, then usage, then alternatives, then per-method parameters and behavioral notes — a logical order with each sentence carrying information. It is dense and slightly long as a single block, but there is little that could be cut without losing method-parameter detail.

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 7-parameter, enum-driven tool with an output schema, the description covers everything an agent needs: method selection, per-method parameter requirements, optional/ignored parameters, unit conventions, error behavior, and the fact that no I/O occurs. Return-value explanation is correctly omitted since an output schema exists.

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 schema alone already documents every parameter. The description still adds value by mapping parameters to methods, noting which are optional per method, clarifying decimal units, and stating that parameters belonging to other methods are accepted and ignored — semantics not derivable from 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?

Opens with a specific verb-and-resource statement ('Market approach: value from comparable transaction revenue multiples or capitalize a royalty stream') and explicitly names the siblings it is not (valuation_income_methods, valuation_royalty_analysis). An agent can distinguish it from related valuation tools without opening any schema.

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 an explicit use condition ('Use when reliable comparable transactions or royalty rates exist') and routes the agent to two named alternatives with the conditions that select them. Both when-to-use and when-to-use-something-else are stated.

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