Add step number

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

Annotations only declare that this is a non-destructive, non-read-only, closed-world mutation, so the description must carry the rest. It adds genuinely useful context — that numbering is automatic and that size should scale with screenshot dimensions — but leaves a serious gap: it never explains how the sequence is determined (does it count existing badges on the canvas? what happens on subsequent calls, or after snipaya_delete_items?).

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?

Two tightly written sentences with zero waste; the core action and placement come first, and the sizing guidance follows. Nothing is repeated from the schema.

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?

There is no output schema, and the tool mutates canvas state with 5 parameters including a nested style object. The description covers placement and size but omits how auto-numbering interacts with existing steps, how it responds on later calls, and whether the returned/affected item identity matters — relevant context for a numbered-sequence tool.

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 already 80%, so the baseline is 3. The description goes beyond the schema by defining 'size' as the badge diameter and giving the scaling rule for large screenshots, and by stating that placement is centered at 'at' — both semantics not present in the structured fields.

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 pairs a specific verb (add) with a specific resource (auto-numbered step badge) and anchors placement at "at". The 'auto-numbered' qualifier and 'for step-by-step guides' phrase implicitly separate it from snipaya_add_text and snipaya_add_shape, but it never explicitly names those siblings as alternatives.

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?

'for step-by-step guides' implies the scenario in which this tool is appropriate, which is more than nothing. However, it gives no explicit when-not conditions and does not route the agent to snipaya_add_text or snipaya_add_shape for non-numbered annotations.

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