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

Annotations only declare the generic safety profile (not read-only, not destructive, not open-world), so the description must add the real behavior — and it does, disclosing idempotency when already open and the editorReady gate before editing. It stops short of covering failure modes such as an unpaired tab or an unknown siteId.

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?

Three short sentences, all load-bearing, with the action and target front-loaded before the idempotency note and the readiness workflow. No padding or repetition.

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 one-parameter tool with no output schema, the description covers what it does, the tab it acts on, idempotency, and the pre-edit readiness check. Only the shape of the returned metadata is left unspecified, which is a minor gap.

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% and the single siteId parameter is already documented as coming from swebsy_list_sites. The description's 'by ID' adds no syntax, format, or constraint beyond what the schema already states, so the baseline 3 applies.

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 ('Open a saved site by ID in the paired tab') plus the return ('its metadata'). The word 'saved' plus the need for a siteId cleanly separates it from swebsy_create_site without opening either schema.

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?

Gives an explicit follow-up workflow: poll swebsy_status for siteId and editorReady before editing, which tells the agent this is a prerequisite step. It doesn't state when-not to use it (e.g., for unsaved/new sites), but the operational context is clear.

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