sleeper_get_userLook up a Sleeper user by username or numeric user ID to retrieve their profile, user ID, and display name. Optionally choose which fields to return.
Get a Sleeper user (profile, user_id, display name) by username or numeric user id.
| Name | Required | Description | Default |
|---|---|---|---|
| fields | No | Keys to keep (comma-separated). | |
| username_or_id | Yes | Sleeper username or numeric user id |
Changes observed during successful MCP inspections.
v1.4.1Input schema / $schemaRemoved value: -"http://json-schema.org/draft-07/schema#"Input schema / properties / fieldsAdded value: +{
+ "description": "Keys to keep (comma-separated).",
+ "type": "string"
+}v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds only the shape of the returned record, which is useful but thin given the lower bar set by the annotations.
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?
A single front-loaded sentence with no filler. It is efficient and readable, though it spends words on the return payload instead of the use case.
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 read-only lookup with full schema coverage, no output schema, and annotations that carry the safety semantics, the description supplies enough for correct invocation. Only the missing routing/usage context keeps it below the top score.
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 essentially restates the username_or_id parameter while ignoring the fields projection parameter. With the schema doing the heavy lifting, baseline 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?
The description states a specific verb and resource ('Get a Sleeper user') and even enumerates the returned payload ('profile, user_id, display name'), so the agent knows exactly what it retrieves. It does not explicitly distinguish itself from nearby siblings such as sleeper_get_user_leagues, keeping it short of a 5.
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?
The phrase 'by username or numeric user id' hints at the keying strategy but there is no when-to-use guidance, no mention of prerequisites, and no routing versus alternatives like sleeper_search_players or sleeper_get_user_leagues. An agent gets no decision support for selecting this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.