Add a bookmark

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

Annotations already declare readOnlyHint=false and destructiveHint=true; the description adds value beyond that by naming the underlying PlacesUtils call, disclosing the default parent folder, and stating that a guid is returned. It does not cover edge behavior such as what happens when the URL is already bookmarked or on invalid guids, so it is not fully transparent.

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 sentences, both load-bearing: the first establishes action and return value, the second establishes default and alternative targeting. No filler or restated title text.

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 three-parameter, fully documented write tool with no output schema, the description covers action, default parent, targeting options, and the return contract (guid). It leaves duplicate-handling and failure behavior unstated, which is the only meaningful 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%, so the baseline is a 3; the description earns above that by explaining the semantic effect of parentGuid (defaults to the bookmarks menu, alternate targets are toolbar and unfiled) rather than just restating its name. It omits the literal guid strings for toolbar/unfiled, leaving the agent to discover them from browser_bookmark_folder.

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 ("Insert a bookmark") plus the underlying API call, and distinguishes itself from the removal counterpart by noting the returned guid is what browser_remove_bookmark needs. An agent can tell this apart from browser_remove_bookmark, browser_list_bookmarks, and browser_bookmark_folder without opening schemas.

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 gives the default targeting behavior (bookmarks menu) and the condition for choosing otherwise (pass toolbar or unfiled guid), and explains the downstream use of the returned guid. It stops short of routing against other bookmark-management siblings such as browser_bookmark_manage or browser_bookmark_folder.

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