duet_pair_fonts

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 disclose the return contents (font families, weights, fallbacks, size scale), which is useful, but says nothing about determinism, whether results are idempotent for the same type_style, or what happens with no parameters at all (all optional). Adequate but incomplete for an annotation-free tool.

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 tight sentences: the purpose is front-loaded, followed by the enum glossary and the return summary. No filler, though the enum expansion is slightly list-like rather than prose.

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?

With no output schema, the description compensates by naming the returned artifacts, and the nested preferences object is fully documented in the schema. Missing only edge-behavior details (defaults when nothing is passed, determinism) for a fully self-contained definition.

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 3, and the description earns above baseline by expanding the type_style enum into meaningful characterizations (clean sans, serif-led, restrained, display-led). It also frames the preferences object's purpose (consistency across sibling tools) that the schema only partially conveys.

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+resource: pick a heading/body/monospace font pairing with a type scale. The resource (typography pairing) is clearly distinct from sibling resources like palettes, shadows, grids and motion. It does not explicitly name or disambiguate from siblings, but the resource alone is unambiguous.

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?

The type_style enum values are glossed (modern = clean sans, classical = serif-led, etc.), which implies when each mode applies, but there is no explicit guidance on when to call this tool versus a sibling, nor any prerequisites or exclusions. Usage is inferable rather than stated.

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