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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds nothing beyond that: no auth prerequisites, no pagination or result-size behavior, no statement of what a 'source' identifier looks like.

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 and no repetition of the title. It is efficient, though so terse that it borders on under-specification rather than optimal density.

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 zero-param list tool with no output schema, the description is the only place a caller could learn what the returned sources represent and how they relate to inspect_rows. It gestures at the inspection workflow but never closes the loop, leaving an agent with a minimally sufficient definition.

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, so there is no parameter meaning for the description to carry. Baseline 4 applies; no compensating detail is required here.

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 ('List') and a qualified resource ('row-level sources available for inspection'), which is enough for an agent to know this is a zero-argument enumeration of data sources. However, it does nothing to separate itself from the many other list_* siblings (list_bindings, list_dimensions, list_kpis), and 'sources' is left undefined.

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 'available for inspection' hints that this is a precursor step to inspect_rows, so usage is implied rather than stated. There is no explicit when-to-use, no exclusions, and no mention of rival discovery tools such as list_bindings or get_inspection_schema.

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