borrow

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

No annotations are provided, so the description carries full burden. It discloses that the tool injects cookies and modifies browser state for subsequent navigate calls, but does not mention side effects, required permissions, or what happens to existing state. The behavioral impact is partially described but lacks completeness.

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 description is concise with two focused paragraphs. The first paragraph front-loads the core purpose and effect, and the second efficiently covers the optional parameter. Every sentence adds useful information without redundancy.

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?

Given the tool has only two parameters, no annotations, and an output schema (whose details are not needed), the description fully covers the tool's effect, parameter meaning, and usage context. It explains the prerequisite for navigate and the fallback logic for profiles, making it complete for the tool's complexity.

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 description provides clear semantic meaning for both parameters: 'domain' is the target for which to borrow an identity, and 'profile' is an optional path substring with documented fallback behavior (first Zen, then Firefox). This adds significant value beyond the bare input schema, which only gives names and types.

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 clearly states the verb 'borrow' and the specific resource: a warmed, already-authenticated identity from a real Firefox/Zen profile. It distinguishes itself from sibling tools by explaining its role in injecting cookies for authenticated navigation, which is unique among the listed tools.

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 implies usage context ('core Wraith move for sidestepping reputation-based defenses') but does not explicitly state when to use versus alternatives or when not to use. There is no direct comparison to other tools, so guidance is implied rather than explicit.

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