Get current user

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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false. The description adds real value beyond them: it discloses the returned identity scopes and explicitly states 'Never returns credentials', which is a security-relevant guarantee the agent could not infer from structured fields.

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 tightly written sentences, front-loaded with the verb and resource, followed by the return scope and the credential caveat. 'Safety classification: READ_ONLY' mildly restates the readOnlyHint annotation but is short and harmless.

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 no parameters and an existing output schema, the description only needs to orient the agent, which it does. It could have noted failure behavior when the session is unauthenticated, but nothing essential for invoking the tool is missing.

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 tool takes zero parameters and the schema is empty, so there is nothing for the description to disambiguate. Baseline 4 applies; the field enumeration is a return-value concern rather than a parameter one.

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 ('Return the Databricks identity this server is authenticated as') and enumerates exactly what that identity includes (username, user id, display name, groups, home folder, workspace). No sibling tool overlaps with identity retrieval, so the agent can distinguish it immediately.

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 by the phrase 'this server is authenticated as' — the tool is for resolving the acting principal — but there is no explicit when-to-use, when-not-to-use, or named alternative. In practice no sibling competes with it, so the missing routing guidance costs little.

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