List available tests

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

Annotations already cover safety (readOnlyHint, idempotentHint, openWorldHint=false), but the description adds genuinely useful behavior: a primary `playwright test --list` path with a source-scan fallback when the install or config is broken, plus the promise that it reports why. It does not mention cost, latency, or whether the fallback results are less complete, which keeps it from a 5.

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 tight sentences: the first front-loads what is listed and what is returned, the second supplies the fallback behavior. No filler, no restatement of the title.

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 partially compensates by naming the returned fields and explaining the dual-path execution. Combined with a fully documented 5-parameter schema and zero required parameters, an agent has nearly everything needed; only the shape of the fallback 'reason' report is left unstated.

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 description coverage is 100%, so every parameter (limit, config, filter, testDir, projectRoot) is already documented with defaults and constraints in the schema. The description adds only the generic phrase 'with optional filtering', which maps loosely to the filter param without adding syntax or format detail. 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 (List) and resource (Playwright tests available in the project) and even enumerates the returned fields (file, line, full title, projects). No sibling tool in the set performs listing, so an agent can distinguish it from run-test, get-run-status, or generate-e2e-test 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?

The mention of 'optional filtering' implies a discovery use case (finding tests before acting on them), but the description never states when to reach for this tool versus run-test or get-run-status, nor does it set any preconditions. Usage is inferable rather than stated.

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