Replace a text range

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

The description adds substantial behavioral detail beyond annotations: the operation is a single atomic batchUpdate that protects against partial failure, new text inherits style at start_index, certain ranges are rejected by the API, and empty replacement behaves like delete_range. This is exactly the kind of context annotations cannot convey.

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 dense, purposeful sentences. The core behavior is front-loaded, and each subsequent sentence adds behavioral constraints or prerequisites without any filler or redundancy.

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 mutating tool with no output schema and six parameters, the description covers prerequisites, failure semantics, style behavior, and invalid ranges. It does not explicitly describe the return value, but for an edit operation this is not a critical omission given the rich behavioral context provided.

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?

The schema already documents all six parameters with 100% coverage, so the baseline is 3. The description adds valuable parameter-level meaning: range boundaries are half-open, indexes must be freshly fetched, and constraints around table cells and paragraph newlines affect valid start/end values.

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 action ('Replaces the content in [start_index, end_index) with new text'), identifies the exact resource, and clarifies edge behavior (empty replacement equals delete_range). This clearly differentiates it from siblings like insert_text or replace_all_text.

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 gives strong contextual guidance: fetch fresh indexes from read_document_text first, notes that indexes are stale after any prior edit, and lists API constraints on valid ranges. It does not explicitly contrast with insert_text or replace_all_text, but it is clear when this tool applies.

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