Read one saved password

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

Annotations only declare readOnlyHint=true, and the description goes well beyond that: it discloses that the return value is a clear-text secret, that both parameters are mandatory, and it gives handling constraints (no chat output, logs, screenshots). This is exactly the kind of context annotations cannot convey for a sensitive read.

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 security warning is front-loaded in the first clause, followed by rationale, then handling rules and prerequisites. Every sentence earns its place and nothing is buried.

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?

Two required parameters, a read-only annotation, and no output schema — the description fills the gaps that matter by characterizing the return value (clear text secret) and the caller's obligations. Nothing needed to call it correctly is missing.

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?

Both parameters are documented at 100% schema coverage, so the schema already does the heavy lifting. The description reinforces that both origin and username are required for lookup, but adds no format, matching, or disambiguation guidance beyond that.

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 — returns a saved password in clear text — and explicitly contrasts itself with listing operations, which is the nearest sibling behavior (browser_list_logins). An agent can tell immediately that this is the deliberate single-credential read, not an enumerator.

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 framing 'always a deliberate act, never a side effect of listing' tells the agent when to invoke it and implicitly routes enumeration to the list tool. It stops short of naming browser_list_logins or stating exclusions explicitly, but the usage context is unambiguous.

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