Undo End-User Merge

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

Annotations provide idempotentHint=true, and description reinforces 'Safe to retry — a second undo changes nothing (fails with already_reverted)'. Also explains 'un-tombstoning' sources, adding behavioral detail beyond annotations. No contradictions.

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 sentences, front-loaded with action, no wasted words. Clearly structured with mechanism, idempotency note, and usage instruction.

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?

Covers purpose, mechanism, idempotency, and parameter source. Lacks description of return value, but given no output schema and practical nature of the tool, this is a minor gap. Overall sufficient for an agent.

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 the single parameter event_id. Description adds reference to list_identity_merges but does not add meaning beyond the schema. Baseline of 3 is appropriate.

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?

Description clearly states 'Undo a previous end-user merge' with specific verb and resource. It details the mechanism (reads merge ledger, re-points FK rows, un-tombstones sources) and distinguishes it from sibling 'merge_end_users'.

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?

Provides clear context: 'Use to correct a wrong identity merge' and instructs to find event_id via list_identity_merges. Mentions 30-day reversibility. Does not explicitly state when not to use, but context is sufficient for correct selection.

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