set_breakpoint

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

With no annotations, the description carries full burden and adds valuable behavioral context: 'Side effects: modifies debugger state (breakpoint added until removed)' discloses mutation, 'Prerequisites: requires an active Chrome tab; target script must be loaded' states requirements, and 'Returns: breakpoint identifier and location confirmation' hints at output. It doesn't cover rate limits or error conditions, but provides solid operational context.

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?

Front-loaded with core purpose, followed by structured sections (Side effects, Prerequisites, Returns, Use case, Alternatives). Every sentence adds value: no repetition, no fluff, efficiently covering key aspects in a compact form.

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 mutation tool with no annotations and no output schema, the description does well: covers purpose, usage, side effects, prerequisites, and return hints. It lacks explicit error handling or detailed output format, but given the schema's 100% coverage and the clear behavioral disclosure, it's largely complete for agent use.

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 parameters are fully documented in the schema. The description adds no specific parameter semantics beyond implying location targeting ('at a specific location'), which the schema already details with line_number, column_number, and script identifiers. Baseline 3 is appropriate as the schema does the heavy lifting.

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 clearly states the verb ('Sets'), resource ('debugger breakpoint'), and location specificity ('at a specific location'), with the effect 'pausing execution when reached'. It distinguishes from siblings like 'pause_on_load' and 'search_scripts' mentioned later.

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?

Explicit guidance is provided: 'Use this to debug specific code paths' states the primary use case, and 'Alternatives: 'pause_on_load' for early script execution, 'search_scripts' to find scripts by pattern' names specific sibling tools with their distinct purposes, helping the agent choose appropriately.

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