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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so the 'Read-only' sentence is redundant. The description does add value beyond the annotations by disclosing the error envelope {error, kind, hint} and the structure of the returned payload, which helps an agent interpret failure modes.

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?

Front-loaded with purpose, then scope, then return/error shape – every clause is informational and there is no filler. It is somewhat dense and telegraphic (semicolon-chained fragments), and the return-shape sentence partly duplicates the existing output schema.

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 one-parameter read tool with an output schema and full annotations, coverage is strong: scope, prerequisite, name-to-parameter mapping and error shape are all stated. Minor gaps remain – nothing on empty results, result limits or whether open-world access is needed for the workspace lookup.

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?

There is a single parameter with 100% schema description coverage ('Fabric workspace, name or id.'), so the schema carries the semantics. The description only restates that a workspace is required and adds no format nuance such as name-vs-id behavior. 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?

States a specific verb (Lists) and resource (data sources in one workspace), and enumerates the item types covered (lakehouses, warehouses, SQL databases, mirrored databases, catalogs) plus GraphQL APIs. That scope cleanly separates it from siblings like list_workspaces and list_tables.

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?

'Requires a workspace' establishes the prerequisite, and the note that a source's name is the `source` and an API's name the `api` of other tools gives concrete downstream-chaining guidance. It never names an alternative or an exclusion (e.g., when to prefer list_tables), so it stops short of 5.

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