Rename Braze user external IDs in bulk to support migration to a new ID scheme. Provide up to 50 current-to-new ID pairs per request.
Rename external IDs for users. Use for migrating to a new ID scheme.
| Name | Required | Description | Default |
|---|---|---|---|
| apiKey | No | Braze REST API key (optional if set via env/header) | |
| restEndpoint | No | Braze REST endpoint URL | |
| external_id_renames | Yes | Array of external ID renames |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. For a mutation tool ('rename'), it omits whether the operation is reversible, what happens to the old ID, permission/auth requirements, and any rate or batch limits, leaving key behavioral traits undisclosed.
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?
Two short sentences with the action front-loaded and no filler. It is efficient, though arguably too terse to be maximally useful for a mutation tool.
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 mutation tool with no annotations and no output schema, the description is under-informative: it never covers side effects, reversibility, or error behavior, and doesn't route the agent away from the similar alias/merge siblings. The schema covers parameters, but behavioral completeness is thin.
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%, and the description adds nothing about the parameters beyond what the schema already documents (including the current/new ID pair structure and the maxItems=50 cap). Baseline 3 is appropriate when the schema does all the work.
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?
States a specific verb and resource ('Rename external IDs for users'), which is clearer than a tautology. However, it does not differentiate from closely related siblings like users_alias_new, users_alias_update, or users_external_id_remove, leaving the agent to infer the distinction.
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?
'Use for migrating to a new ID scheme' gives an implied usage context, but it offers no when-not-to-use guidance and never names the adjacent alias/merge/remove tools an agent might otherwise pick.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.