Add KPI Metric Dashboard Slide

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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=true, so the safety profile is covered. The description adds layout constraints (56pt hero metrics, >=24pt diagnostic text, Overfitting/direction boxes) but does not say what happens when a slide already exists at slide_number — the 'cập nhật' path that matters most for a write tool — nor anything about permissions or overwrite scope.

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?

A single front-loaded sentence that leads with the action and then qualifies the layout and typography constraints. No filler or repetition, though the parenthetical font-size details make it dense and harder to scan than it needs to be.

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 7-parameter write tool with no output schema, the description covers purpose and visual constraints but leaves the update/overwrite behavior and the resulting slide content unstated. Annotations carry the safety signal, so the remaining gap is not severe, but it is not complete for a tool that can replace an existing 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 every parameter is already documented in structured form and the baseline is 3. The description adds a little semantic color by indicating what diagnostic_boxes should contain (Overfitting assessments / forward-looking direction), but gives no guidance on title, presenter, subtitle_context, or how kpi_metrics ordering maps to the hero row.

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 gives a specific verb pair ('Tạo hoặc cập nhật') plus the resource ('slide trong bài thuyết trình') and pins down the exact layout being produced ('Dashboard các chỉ số lớn (Hero Metrics 56pt)'). That level of layout specificity effectively distinguishes it from siblings such as canva_add_swot_matrix or canva_add_process_timeline, though it never names an alternative 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 only implied by the layout name: an agent can infer this is for KPI/metric-centric slides. There is no statement of when to prefer it over canva_generate_deck_from_data, canva_add_tasteful_slide, or other layout tools, and no when-not conditions. 'Tạo hoặc cập nhật' does at least signal it is safe to reuse for an existing slide position.

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