arc_open_url

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

Annotations indicate readOnlyHint=false, aligning with the navigational modification. The description adds the behavior of falling back to the active tab when tab_id is omitted, but doesn't disclose potential side effects like page load behavior or error handling for invalid tab IDs.

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 a single, front-loaded sentence of 12 words. Every word is necessary; no redundancy or verbosity.

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 presence of an output schema and sibling tools, the description covers the basic action but lacks details on navigation semantics (e.g., whether it changes the current page URL, any loading behavior). It is adequate but not comprehensive.

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 parameter descriptions are missing from the schema (0% coverage). The description clarifies that tab_id defaults to the active tab, which adds meaning. However, it does not specify URL format or constraints (e.g., must be valid URL).

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 it navigates an Arc tab to a URL, specifying the active tab as fallback. It distinguishes from siblings like arc_create_tab (which likely creates a new tab) but could be more explicit about differentiating creation vs navigation.

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?

No explicit guidance on when to use this tool versus alternatives. The description implies it is for navigating existing tabs, but fails to mention that arc_create_tab should be used for new tabs.

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