fast_edit_block

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

No annotations are provided, so the description carries full disclosure burden. It only states 'safely replace', which is vague. It does not mention that backups are created by default (as per schema), preview capabilities, or behavior on mismatch. The description adds minimal behavioral context beyond the schema.

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 a single concise sentence of 9 words, making it easy to read and process. It front-loads the core action. However, it may be too sparse, missing important details that could be added without significant bloat.

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?

Given the tool's complexity (8 parameters, no output schema, no annotations), the description is insufficient. It does not explain the return value, error handling, or how 'block editing' differs from other editing approaches. The description leaves the agent with many unknowns.

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 the input schema already documents all 8 parameters. The description adds no additional explanation or context for the parameters. Baseline score of 3 is appropriate as the description does not detract but also does not enhance semantic understanding.

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 'precise block editing' and 'replace exact matches', clearly indicating the tool's purpose: making exact text replacements in files. It is a specific verb-resource pair. However, it does not differentiate from sibling tools like fast_edit_blocks or fast_safe_edit.

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 offers no guidance on when to use this tool versus alternatives. It mentions 'safely replace exact matches' but does not specify scenarios or provide exclusions. With many sibling editing tools, the lack of usage context is a significant gap.

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