List, set, move or remove search engines

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

Annotations only set readOnlyHint=false; the description does disclose mutating methods such as setDefault, moveEngine, removeEngine, and restoreDefaultEngines, which aligns with that annotation. However, it does not explain effects, whether reset is destructive, required permissions, or error behavior, and the add* family it describes is not in the action enum.

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?

The description is front-loaded with a short purpose sentence, but the remaining space is spent on an internal-module tangent rather than tool-selection or invocation guidance. That second sentence reads as implementation trivia from the calling agent's perspective.

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 mutating tool with no output schema, the description should cover action semantics and mutation effects; instead it mostly explains SearchService internals. An agent cannot reliably decide between this and browser_get_search_engine or browser_add_search_engine from the description alone.

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%, so name, action, and position are already documented in the schema. The description adds no conditional parameter requirements or syntax beyond that, so the 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?

The opening 'Manage Firefox search engines' names the resource but uses a broad verb and never distinguishes this tool from siblings such as browser_get_search_engine, browser_add_search_engine, or browser_search_prefs. The title and action enum carry the specific operations, but the description itself does not.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no routing to alternatives. The bulk of the text is an implementation note about moz-src module ids, leaving the agent to infer that list/set-default/move/remove/reset belong here and adding engines belongs elsewhere.

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