session_snapshot

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

Even with annotations present, the description adds meaningful behavioral detail: it skips zero-size and hidden elements, caps labels at 120 characters, stops at 200 elements, and explains the ref handle format. This goes beyond the idempotent and non-destructive hints already supplied.

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?

Three sentences, no filler. The first sentence states purpose and return shape, the second explains ref semantics and sibling-tool usage, and the third lists limits. Every sentence earns its place.

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 one optional parameter and no output schema, the description fully covers the output structure, element shape, ref semantics, sibling relationships, and truncation behavior. Nothing needed for correct invocation is missing.

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%: the only parameter, tabId, is already documented as 'Tab to snapshot; uses the active tab when omitted.' The description adds no additional parameter semantics, so the baseline of 3 is appropriate.

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 states a specific verb and resource: 'Capture a semantic map of a page for deciding what to act on.' It also distinguishes itself from session_read_page by framing this as the interactive-element snapshot versus a read-oriented page snapshot. The title 'Snapshot interactive elements' reinforces the purpose.

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?

It explicitly gives the when-to-use rule: 'Prefer this over session_read_page when the goal is to interact rather than to read.' It also explains that the returned @eN refs are accepted by session_click, session_fill, session_type, session_select, and session_press, making the workflow clear.

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