spine_add_slot

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

No annotations are provided, so the description carries the full burden. It does disclose real behavior: draw order follows list order with later slots on top, and `attachment` must already exist in a skin. It omits whether the operation is reversible, how existing slots' indices shift on insert, and what happens on an out-of-range index.

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?

Front-loaded with the core behavior in the first sentence and draw-order semantics immediately after, followed by a compact Args block. Slightly redundant that the Args list restates what the schema already exposes as bare property names, but nothing is wasted.

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?

An output schema exists, so return values need not be described, and the mutation itself is understandable. Still, for an 8-parameter creation tool with zero annotations and zero schema descriptions, the coverage of the required parameters and the index-shifting side effects is too thin to call complete.

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 0%, so the description must compensate, and it partly does: it gives the color format (RRGGBB/RRGGBBAA) and spells out the blend options (normal, additive, multiply, screen) that the schema leaves as an unconstrained string — valuable since there are no enums. However, three parameters (project, name, bone) get no explanation at all, and `attachment`/`dark` are described only in the loosest terms.

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 and resource ("Add a draw-order slot") with its anchor constraint ("attached to an existing bone"), which cleanly separates it from spine_add_attachment, spine_add_bone and spine_update_slot. An agent can tell what this creates without opening the schema.

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: it explains what a slot is and that `index` inserts at a draw position rather than appending, but never says when to reach for this tool over spine_add_attachment or spine_update_slot, nor what prerequisites exist (open project, skin already containing the attachment). No when-not guidance at all.

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