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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: revoked identities are excluded from results, the status enum values, and the interpretation rule that an 'active' row with an old last_known_good_at likely needs re-login. That is exactly the kind of behavioral signal annotations cannot carry.

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?

Front-loaded with purpose and usage before the field inventory, and every clause carries information. It is a single dense paragraph, though, and the long field enumeration could be broken up for faster scanning.

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?

There is no output schema, so the description carries the full burden of describing return values, and it does so thoroughly: identity_id, name, origin, registrable_domain, status, timestamps, has_credentials, can_delete, and channel account health. An agent knows exactly what it will get back and how to interpret it.

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 coverage is 100%, so both parameters are already documented, and the description's note about `site` filtering by origin/domain substring largely restates the schema. It adds a concrete example ('websummit') but says nothing about `in_workspace`, so it does not meaningfully exceed the schema baseline.

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 ('List this workspace's browser identities') and anchors it to a concrete surface ('the /connections page, over MCP'). It is clearly distinguishable from siblings like browser_create_identity, browser_delete_identity and browser_handoff, which the description references by name.

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?

Explicitly says when to use it: 'before creating, re-authenticating or deleting one, so you never guess a name or make a duplicate.' It also names the follow-up path (re-login via browser.handoff) when a row looks stale, giving both when-to-use and what-to-do-next guidance.

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