firefox_context

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

Annotations already declare readOnlyHint, idempotentHint, non-destructiveness, and openWorldHint, so the safety profile is covered. The description adds genuinely non-obvious framing by labelling the returned content 'untrusted context' and tying it to an 'authorized' document, but it does not say what happens on unauthorized access or how frame-scoped reads behave, which is the main behavioral gap.

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?

A single front-loaded sentence with no filler, and the returned fields are listed before the untrusted-context caveat. It is efficient, though the phrase 'the authorized document' front-loads an unexplained qualifier rather than the tab source.

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 and 0% parameter coverage, the description should at minimum explain the tab/frame selection and the authorization precondition. It lists the returned fields (URL, title, selected text) but leaves both parameters and the failure mode undocumented, making it only minimally sufficient for a two-parameter read tool.

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?

Both parameters (tabId, frameId) have zero schema description coverage, so the description carries the full burden, yet it never mentions either parameter. An agent must infer that tabId selects the tab and frameId the subframe; nothing explains defaults, frame scoping, or whether frameId may be omitted.

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 description names a specific verb (Read) and enumerates the resource returned: the document's URL, title, and selected text. It is clear what the tool yields, but it does not distinguish itself from the sibling firefox_read_page, which an agent must otherwise disambiguate by opening both schemas.

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 an alternative such as firefox_read_page or firefox_frames. The word 'authorized' hints that prior access must be granted, but the description never states that prerequisite or what to do when it is absent.

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