ui_sources

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

With no annotations, the description carries the full burden, and it does disclose one important trait: check=true triggers a live search per source. It omits cost/latency implications, whether failing sources cause errors or are just flagged, and what the unchecked listing contains.

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?

One compact sentence with no waste, and the base behavior is front-loaded ahead of the optional mode. The semicolon construction is dense but readable; a touch more spacing would help without adding length.

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 simple one-parameter tool with no annotations and no output schema, the description covers the core behavior and the mode switch. It leaves return shape ambiguous (a list of sources vs., with check, per-source status) and says nothing about failure handling, so it is adequate rather than complete.

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 0%, so the description must compensate for the single parameter, and it does: it explains that check=true performs a live search and changes the response to a health report. The default value (presumably false) is not stated, which is the only gap.

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 gives a specific verb and resource: 'List the UI library sources'. It also discloses the dual mode (listing vs. live verification), which separates it from pure search siblings like library_search and search_ui, though it never names those siblings explicitly.

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?

It states the condition for setting check=true ('run a live search ... to report which ones work right now'), which implies a health-check use case. It does not say when to prefer this over library_search or search_ui, nor when check should be left off beyond the implicit default case.

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