Installed themes

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

Annotations already declare readOnlyHint=true, and the description adds real behavioral context beyond that: the mutual-exclusion semantics of theme activation and the resulting reversibility. It does not describe the exact return fields (id, name, active flag), which is the only missing behavioral detail for a listing 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 compact sentences, front-loaded with what is returned and followed by the actionable switch path. No filler or repetition of the title.

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 zero-parameter read-only listing tool with no output schema, the description covers what is listed, what the key state is (active theme), and how to act on the result. Only the exact shape of returned entries is unspecified, which is a minor 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the schema is trivially complete. Baseline 4 applies; no parameter guidance is needed.

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 ('List installed themes') plus the added dimension of which one is active, and scopes it to AddonManager type 'theme', which separates it from the generic browser_list_addons. It does not acknowledge the equally relevant sibling browser_set_theme, so differentiation is clear in intent but slightly incomplete.

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 concrete next-step guidance: use browser_set_addon_state on a theme id to switch, and explains that enabling a theme disables the previously active one so the change is reversible. It offers no explicit when-not-to-use or comparison against browser_list_addons, and oddly omits the existing browser_set_theme sibling.

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