browser_passkey_install

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

With no annotations, the description carries the behavioral burden. It does disclose that the tool modifies the current browser context and must be called before navigator.credentials is used. However, it does not mention idempotency, whether repeated calls overwrite existing authenticators, or how the installed authenticator interacts with browser_passkey_create/delete.

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 concise, front-loaded sentences with no filler. The first sentence states the action, and the second provides the critical timing constraint.

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-parameter setup operation with no output schema, the description covers the essential action and timing. It could strengthen completeness by relating this tool to sibling passkey operations, but the core calling context is sufficiently specified.

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 input schema has zero parameters, so the no-parameter baseline applies. The description adds relevant contextual information about the current browser context, but there are no parameter semantics to elaborate on.

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 uses a specific verb ('Install') and resource ('Patchright's virtual WebAuthn authenticator') and scopes it to the current browser context. It is clearly distinguishable from sibling tools like browser_passkey_create, browser_passkey_list, and browser_passkey_delete.

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 description explicitly states when to call the tool: before a page first uses navigator.credentials. This gives the agent clear timing guidance, though it does not explicitly discuss alternatives or when not to use the tool.

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