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

Annotations already declare idempotentHint=true, destructiveHint=false, and readOnlyHint=false. The description adds value by specifying 'optimistic concurrency' and 'idempotent mutation receipt', which inform the agent about concurrency handling and return semantics. This is additive beyond annotations, though it could mention what happens on conflict or failure for a 5.

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?

The description is a single, focused sentence — concise and front-loaded with the core action ('Create or update a Story Kit'). It adds two key behavioral traits (optimistic concurrency, idempotent mutation receipt) without waste. However, given the high parameter count and low schema coverage, a few more words on parameter behavior might be warranted, dropping it from a 5.

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?

The tool has 12 parameters, 25% schema coverage, and no enums, but offers an output schema. The description covers the high-level behavior (create/update, concurrency, idempotency) but does not explain what the output schema contains, how locations or facts are structured, or error handling. With moderate complexity and partial schema coverage, a 3 is appropriate — adequate but incomplete.

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 description coverage is only 25%, meaning the description must compensate, but it only mentions the three required parameters (name, visualStyle, idempotencyKey) semantically. The term 'Canonical visual-style contract' clarifies visualStyle, but for 12 parameters, most (facts, locations, characterIds, etc.) receive no additional explanation. The output schema exists, which slightly reduces the burden, but the description is insufficient to fully guide parameter use.

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 clearly states 'Create or update a Story Kit' — a specific verb and resource combination that distinguishes it from siblings like story_kits_get and story_kits_list. However, it lacks the exclusive scope (e.g., 'bounded to a workspace') that would make it a 5, and the 'idempotent mutation receipt' phrase is somewhat technical and not as immediately graspable.

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?

There is no explicit guidance on when to use this versus alternatives. The description mentions optimistic concurrency and idempotency, which imply it is used for safe create-or-update operations, but it does not name sibling tools (like story_kits_get for reading) or state when not to use it. The 'apply' name hints at upsert behavior, but context is missing for a higher score.

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