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

With no annotations, the description carries the full burden. It usefully discloses what the added font enables (fontFamily/font-family usage) and that it attaches to 'the open project', but says nothing about permissions, idempotency of duplicate adds, failure modes for unknown families, or persistence across sessions.

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, purpose front-loaded, with the follow-up usage and the scope exclusion following in logical order. No filler words.

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 single-parameter add tool with no annotations and no output schema, the description covers purpose, post-conditions, and scope. It could mention the return value or duplicate-handling, but it is largely sufficient to call 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 100%, so the 'family' parameter is already documented with an example ('such as Caveat'). The prose only reinforces that the name comes from search_google_fonts, adding little beyond the schema's own description. 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 ('Add a Google Fonts family to the open project') and immediately delineates scope by noting built-in editor fonts are excluded. An agent can distinguish it from search_google_fonts (discovery) and the many add_* siblings (assets, divs, phones).

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 a clear downstream use case ('use it as fontFamily on text layers or as font-family in card html') and an explicit exclusion ('Built-in editor fonts need no adding'). It implies the search-first workflow by naming search_google_fonts, but does not explicitly state the ordering or when this call must be skipped.

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