list_global_sources

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

readOnlyHint already covers the safety profile, so the bar is lower, and the description still adds real value: the return shape ('compact summary per source') and the API quirk that unfiltered calls may not return all types. That quirk is exactly the kind of behavioral trait that prevents a wrong call, though pagination/limits remain unstated.

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?

Three compact sentences with zero filler: what it lists, what it returns, and the one thing to do when calling it. Nothing is buried or repeated.

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 output schema, the description usefully signals the compact-summary return, and there is only one optional param which the schema fully documents. Complete enough to call correctly, with only minor gaps around result size or pagination behavior.

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 coverage is 100% so the baseline is 3, but the description goes beyond the schema by giving example values ('cart', 'popup') and the reason the filter matters — that the API may silently drop types without it. That rationale is meaning the schema alone does not convey.

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 ('List global sources') and grounds it with examples ('cart, popup'), which distinguishes it from the detail/contents siblings like get_global_source_detail. It never names an alternative explicitly, so the differentiation is inferred rather than stated.

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?

Gives concrete, actionable guidance — always pass 'component' because the API may omit types without a filter — which is a real usage condition rather than boilerplate. It stops short of saying when to prefer this over get_global_source_detail or search_global_source_elements, so it is clear context without explicit alternatives.

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