Merge End-Users

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

The description discloses critical behavioral traits beyond annotations: all FK rows are re-pointed, sources are tombstoned, and the operation is a write reversible for 30 days. This gives the agent full awareness of side effects and reversibility, especially important since annotations are all false.

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 three sentences long, dense yet well-structured. It front-loads the core purpose and result, then efficiently conveys side effects, reversibility, and prerequisites without unnecessary verbosity.

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 complex write operation with no output schema, the description covers all essential context: the merge result includes the event id (retrievable later), FK re-pointing, tombstoning, reversibility window, and the mandatory prerequisite of using get_device_candidates. This is complete for an agent to decide and execute correctly.

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?

The input schema already provides thorough descriptions for all parameters (100% coverage), so the description adds minimal new parameter-specific semantics. It reiterates that the two IDs are required, which is already in the schema, but does not clarify any additional formats or constraints.

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 action ('Merge source end-users into a target') and the expected result. It distinguishes itself from siblings by explicitly referencing related tools like get_device_candidates and unmerge_end_users, making its role unambiguous.

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 explicit guidance: 'Get the candidate ids from get_device_candidates first — never guess which users to fold together.' This is a clear directive on when to use this tool and what prerequisite steps are needed. Also mentions unmerge_end_users for reversal, offering a complete usage context.

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