set_breakpoint

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It covers side effects ('modifies debugger state (breakpoint added until removed)'), prerequisites, and return value. While it doesn't mention edge cases like duplicate breakpoints or persistence across navigations, the disclosed side effects and prerequisites are substantive and helpful for an agent deciding to call or not.

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 compact and well-structured: two core sentences plus an alternatives sentence. It front-loads the purpose, then side effects, prerequisites, return, and usage guidance. No fluff—every sentence earns its place, and the alternatives are efficiently listed.

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 tool with 7 parameters and no output schema or annotations, the description provides the essential context: purpose, side effects, prerequisites, return, and alternatives. It doesn't detail parameter relationships or error states, but the schema handles parameter specifics. The description is sufficiently complete for an agent to decide on invocation, though a note on persistence or failure handling would push it to 5.

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% per context signals, so the baseline is 3. The description does not add any parameter-specific details beyond the schema; it only mentions the return value, not the parameters themselves. Since the schema already thoroughly explains each parameter with constraints and interactions, the description adds no extra semantic value for parameters, hence a 3.

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 opens with a clear verb and resource: 'Sets a debugger breakpoint at a specific location, pausing execution when reached.' It names the exact action and resource, and distinguishes itself from siblings by explicitly mentioning alternatives like 'pause_on_load' and 'search_scripts', making the tool's purpose unambiguous.

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 description explicitly states when to use: 'Use this to debug specific code paths,' and provides alternatives with conditions: 'Alternatives: ''pause_on_load'' for early script execution, ''search_scripts'' to find scripts by pattern.' It also states prerequisites (active tab, script loaded), giving clear guidance on when it can and should be used.

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