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

No annotations exist, so the description carries the full burden. It does add one useful behavioral fact — 'Cookie values are not returned' — which tells the agent secrets are not exposed in the response. But for a write/persistence operation it omits whether an existing saved session is overwritten, where the data is stored, and what permissions or session state are required.

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 short sentences with zero filler; the core action and scope are front-loaded, and the return-behavior caveat follows immediately.

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?

No output schema and no annotations mean the description alone must cover behavior, and it only covers the response caveat. Missing pieces — overwrite semantics of an existing saved session, 'site' format, and required browser/session state — matter for calling this correctly.

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 only 33% (only identity_id is documented), so the description must compensate; it partially does by framing cdp_url as a browser endpoint URL and site as a single site. However, it gives no format conventions for 'site' (domain vs. full URL) and nothing about cdp_url validity, leaving both required parameters underspecified.

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 ('Save cookies and localStorage') with a clear scope limit ('for one site') and the source ('browser at cdp_url'). It does not explicitly name restore_session as its counterpart, so sibling differentiation is only implied.

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?

Usage is implied by the pairing with restore_session in the sibling list, but the description never says when to call this versus restore_session, nor states any prerequisite such as the browser needing to be an authenticated live session. No exclusions are given.

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