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

Annotations already establish read-only, idempotent, non-destructive, closed-world, but the description adds substantial behavioral context beyond them: the PERMISSION_REQUIRED failure mode and required relay-then-retry handling, and the fact that provider keys are the user's own and cannot be set from this tool. It also discloses conditional return shapes (providersAdvice present only when a provider is unusable).

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?

The critical routing sentence is front-loaded and the providers block is clearly delineated, but the PERMISSION_REQUIRED behavior is stated twice (once in the first paragraph, again in the closing line), which is mild redundancy in an otherwise dense description.

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 carries the full burden of describing returns, and it does: project fields, the conditional `folder`, the `providers` map with its four status values, and the conditional `providersAdvice` note. An agent knows what it will get back and how to handle the error path.

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?

Only one parameter and the schema already documents `token` at 100% coverage, including that it selects which browser to drive. The description adds no format, lifetime, or reuse guidance for the token, so the schema is doing all the work — baseline 3.

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 plus the exact fields returned (id, name, lastOpenedAt, folder), and explains what `folder` implies for media pooling. It also positions itself against the sibling tools by declaring itself the entry point that yields the projectId every other tool needs.

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 explicit ordering guidance — 'Call first to find the projectId every other tool needs' — and prescribes the recovery flow for PERMISSION_REQUIRED (relay the instruction to the user, then retry). It does not name sibling alternatives such as open_project or new_project or state when not to use it, so it stops short of a 5.

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