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

The description discloses key behavioral traits beyond the destructiveHint annotation: the full number is stored in a secret store, only the last four digits are recorded and returned, and no tool reads the number out again. This adds meaningful context about data handling and irreversibility, though it does not cover all potential side effects (e.g., overwriting behavior).

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?

The description is four sentences with no fluff. It front-loads the core purpose, then provides essential behavioral and privacy instructions. Every sentence contributes meaning, and the structure is clear and efficient.

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?

Given the tool has an output schema, the description needn't explain return values. It covers the purpose, data handling, and user interaction. It does not mention prerequisites like existence of the formation or shareholder, or whether the operation overwrites an existing identifier, but these are minor gaps given the schema and sibling context.

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 67% with minimal 'UUID value wrapper' descriptions. The description clarifies that taxIdentifier is the SSN/ITIN and that only its last four digits are recorded, adding meaning beyond the pattern. However, it does not elaborate on formationId or shareholderId beyond what the schema already implies, so the added value is moderate.

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 states a specific verb ('files') and resource ('one shareholder's Social Security Number or ITIN against a formation'), making it distinct from siblings like formation_add_shareholder or formation_update_shareholder. It clearly identifies the tool's role without ambiguity.

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 gives operational guidance on handling the sensitive number (ask directly, pass once, never repeat) but does not specify when to use this tool versus alternatives, nor any exclusions or conditions. There is no mention of how it differs from formation_update_shareholder or when it should be preferred.

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