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

Annotations already indicate destructive and idempotent behavior; the description adds valuable context by specifying the compare-and-swap precondition, mandatory evidence and reason, and the immutable correction record in subject provenance. This goes beyond the annotations without contradicting them.

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?

Three dense sentences carry the action, preconditions, side effects, and alternative routing. There is no filler or repetition of schema content.

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 description gives strong high-level context for a destructive, idempotent correction operation, but with eight required parameters and no output schema, the missing parameter-level guidance leaves meaningful gaps. It is adequate for choosing the tool, less so for constructing a fully correct call without additional inference.

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 only 13%, so the description must compensate for eight required parameters. It clarifies expected_value and emphasizes evidence_sources/reason, but leaves subject_id, field_root, field_path, corrected_value, and especially idempotency_key with little or no added meaning. The agent gets structure but not semantics for most parameters.

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 opens with a precise verb and object: 'Replace one incorrect identifier or attribute using the stable subject ID.' It also differentiates itself from enrich_subject by stating that this tool corrects existing facts rather than adding missing ones.

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 explicitly routed: 'Use enrich_subject for missing facts; never use this operation merely to add a value.' It also states the precondition that the current value must match expected_value, giving the agent a clear gate for when invocation is appropriate.

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