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

Annotations only say readOnlyHint=false, destructiveHint=false, openWorldHint=false; the description adds real behavioral content beyond them: the edit is applied and re-rendered immediately, other slides are untouched, omitted fields are preserved ('A field left out stays as it is'), and the call costs nothing. It does not say whether prior text is recoverable or what permissions the slideshow requires.

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?

Four short sentences with no filler; the scope constraint is front-loaded and 'Free' and the omitted-field rule each earn their space. The opening is somewhat elliptical ('New words for one finished slide ... drawn again on its picture') and could be plainer without losing content.

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 non-destructive single-slide edit with a fully documented schema and no output schema, the definition covers mutation scope, partial-update semantics, cost, and text formatting. The remaining gap is the result of the call (what is returned after the redraw) and how heading and text interact on the same slide.

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 coverage is 100%, so all four parameters already carry descriptions and the baseline is 3. The description does add value for the `text` field by explaining line-break and blank-line formatting and how lines map to text blocks on layout-matched slides, but says nothing extra about `heading`, `slide`, or `slideshow_id` beyond 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?

The first sentence names a concrete verb and resource ('New words for one finished slide of a studio slideshow') and states the scope boundary that matters most: redrawn on that slide's picture only, 'without remaking the other slides'. That separates it from sibling mutators like swap_slide_photo or add_text_to_photo, though the phrasing is indirect ('new words for' rather than 'replace the text of') and no sibling is named explicitly.

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?

Usage is implied rather than stated: the 'one finished slide ... without remaking the other slides' scope tells an agent this is the targeted-edit path, and 'Free' signals it costs no credits (relevant against sibling tools like get_credits). There is no explicit when-to-use/when-not-to-use guidance and no pointer to an alternative for whole-slideshow regeneration.

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