Resolve an Instagram numeric user ID to its current username, so accounts remain identifiable after handle changes.
Instagram user id to username. The current handle for a numeric user id, which still works after the account renames itself.
Cost: 2 credits.
| Name | Required | Description | Default |
|---|---|---|---|
| user_id | Yes | Numeric Instagram user id. Pass this or username. |
Changes observed during successful MCP inspections.
v0.1.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine context beyond them: the returned handle is stable across account renames, and the call costs 2 credits. It does not cover failure behavior for invalid or deleted ids.
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 tight sentences plus a cost line, with the core purpose front-loaded in the first phrase. Every sentence carries information an agent needs; nothing is padded.
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?
With one parameter, no output schema, and annotations covering the safety profile, the description adequately covers purpose, return semantics ('the current handle'), and cost. Minor gaps remain around invalid-id behavior, but the essentials for correct invocation are present.
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 single parameter is fully documented in the schema (type, example, 'Numeric Instagram user id'). The description adds no syntax or format detail beyond 'numeric user id', so baseline 3 applies.
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 states a specific transformation with direction: 'Instagram user id to username,' which is enough to distinguish it from the inverse sibling instagram_user_id. It does not name that sibling explicitly, but the direction is unambiguous, so an agent can select correctly.
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 implied rather than stated: the note that the handle 'still works after the account renames itself' hints at when this stable resolution is preferable. There is no explicit when-to-use, when-not-to-use, or named alternative (e.g., pointing to instagram_user_id for the reverse lookup).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.