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

Adds real value beyond the annotations by stating 'Does NOT change the site' and naming the follow-up mutation tool, so the agent understands the read-then-apply flow. It leaves one gap: with no output schema, it never says how the user's choice comes back (returned value vs. later read), which matters for a 'show for the user to pick' 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 sentences, zero waste, with the non-mutating constraint front-loaded before the follow-up instruction.

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, non-mutating presentation tool this covers intent, side-effect profile, and the follow-up step. The only missing piece is the return/selection behavior, which the description must carry since there is no output schema.

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 description coverage is 100% and the options schema already spells out the nested styleGuide fields, so the schema does the heavy lifting. The description adds only the 'heading + body Google Fonts' framing, and its fixed '3 pairings' conflicts mildly with the schema's maxItems of 10 and with the optional palette/accentFontFamily fields.

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?

Specific verb plus resource: 'Show 3 font pairings (heading + body Google Fonts)'. It also disambiguates from the mutation path by naming set_theme as the tool that actually applies a pairing.

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?

Makes the workflow position explicit — present options to the user, then apply the pick separately with set_theme. It stops short of saying when *not* to call it (e.g. when the site's fonts are already decided) or how it relates to the sibling suggest_palettes.

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