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

The description adds useful context about string storage and null-to-clear behavior, but this largely duplicates schema descriptions and does not significantly go beyond the annotations (idempotent, non-destructive). The description is consistent with annotations and adds modest value.

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 a single, focused sentence with two clear clauses. Every word earns its place; no fluff or repetition.

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 simple tool with a well-defined schema and a known output schema, the description captures the core action and the key special behavior (clearing values). It is complete enough for an agent to distinguish and invoke correctly, though slightly more context on entity types would be nice.

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 description coverage is 100%, so the baseline is 3. The description clarifies the null-to-clear behavior for the 'value' parameter, which matches the schema, but does not add substantial meaning for other parameters beyond what the schema already documents.

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 clearly states the tool's function with a specific verb ('Set or clear') and resource ('custom field values for a CRM entity'). It effectively distinguishes this from siblings like get_custom_field_values (read) and create/update_custom_field (managing definitions).

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention scenarios, exclusions, or relationships to sibling tools like get_custom_field_values or create_custom_field, leaving the AI agent to infer context.

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