Update Chapters Customizations

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

Goes well beyond the annotations: it discloses partial-update semantics (only supplied fields change), null-deletes-field behavior (the destructive mechanism behind destructiveHint), token/permission prerequisites including delegated tokens, the mandatory confirm=true, and side effects (may share access, notify people, incur charges). This is rich behavioral context beyond what readOnlyHint/destructiveHint declare.

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-loads the crucial behavior (partial update, null deletion) in the first two sentences, then layers auth and confirm requirements. The permission block is somewhat verbose but each element is actionable; the trailing side-effect sentence is broad but relevant for a destructive write.

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 complex nested mutation with no output schema, the description covers the essential operational facts an agent needs (partial semantics, deletion, auth, confirmation). It omits how chapterList merges/replaces or the meaning of the "deleted" string field, leaving minor gaps for a tool this complex.

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 high (83%), so the nested plugin/chapters/chapterList fields are already documented. The description adds conceptual meaning for the payload (partial update, null deletes) but does not explain the payload-vs-body-flags-vs-payload_file routing or per-field behavior beyond the schema. Baseline 3 is appropriate.

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 ("Applies a partial update to a media's chapter customizations"), scoping to chapters specifically and distinguishing it from the many sibling update_*_customizations tools. An agent can identify the target resource 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?

Provides meaningful operational context (confirm=true required, permission/token requirements, delegate scope) but never explicitly states when to prefer this over siblings like get_chapters_customizations or the generic update_customizations. Usage is implied rather than stated, and no exclusions are given.

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