Format text

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

Annotations already declare a non-read-only but non-destructive mutation, so the safety profile is covered. The description adds real behavioral context by specifying zero-based UTF-16 offsets, which prevents an off-by-one/encoding error. It does not disclose whether properties not passed are left untouched or reset, or whether this requires the target to already contain text.

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 short sentences, zero filler, with the operation and target front-loaded before the index convention and the prerequisite. Nothing needs trimming.

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?

A 13-parameter mutation tool with no output schema and only partial annotation coverage needs more than this. Target type and index semantics are covered, but the agent is left unsure about merge-vs-replace behavior for omitted style properties and about what the response confirms.

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 13 parameters at 69% schema coverage, the description compensates where it matters most by defining the index semantics (zero-based UTF-16 offsets) that the schema only labels "Start index"/"End index". The remaining style flags (bold, italic, color, fontFamily) are self-explanatory and partly documented in the schema.

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?

States a specific verb+resource: styling a character range inside a shape or text box. The scope (character range within an existing text-bearing element) is precise enough to act on. It does not name the adjacent siblings it differs from (update_text, replace_all_text), so an agent must infer that this is formatting-only rather than content replacement.

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?

"Use get_slide to find text first" gives a concrete prerequisite and implied workflow, which is genuinely useful. However, it never says when to choose format_text instead of update_text or replace_all_text, nor whether format_text is the only way to change styling versus recreating text.

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