Set JavaScript breakpoint

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

Annotations already disclose readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the description need not repeat those. It adds the useful context of operating 'through the local Chromium debugger.' Yet it does not mention that setting a breakpoint affects subsequent execution or that a session must already be running.

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?

One tight sentence of 14 words carries the core purpose, key parameters, and mechanism with zero filler. The most important information is front-loaded.

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 small mutation tool with only 4 parameters and a provided output schema, the description is nearly sufficient. It lacks an explicit requirement for an active debug session, but the sessionId parameter and sibling tool set make that inferable.

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?

With 0% schema description coverage, the description carries the burden of explaining parameters. It clarifies sourceUrl and that line is one-based (matching the schema min=1), but gives no guidance on sessionId or the optional column meaning.

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 ('Set'), a concrete resource ('breakpoint by source URL and one-based line number'), and the mechanism ('local Chromium debugger'). This clearly distinguishes it from sibling tools like web_debug_evaluate or web_debug_control, which perform different debug actions.

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?

The usage context is implied: an agent can infer this is for pausing exection at a specific line in a supported debug session. However, it does not explicitly state when to choose this tool over alternatives, nor any preconditions like requiring an active web session.

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