update_chapter

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

Annotations already signal readOnlyHint=false and destructiveHint=false, so the non-read-only nature is covered. The description adds the concrete behavior (changing title or moving timecode) but does not discuss side effects, overwriting semantics, or response behavior; it also does not contradict the idempotentHint.

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 with no filler. Every word contributes to the agent's understanding of what the tool does.

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 core purpose is clear, but the wording 'or' is ambiguous about whether title and timecode can be updated together (the schema allows both). It also doesn't specify that at least one optional field should be present for a meaningful update, which is a relevant gap for a mutation 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 description coverage is 100%, so the schema documents all four parameters. The description paraphrases title and timecode_seconds but adds no new constraints, units, or guidance on whether one or both fields should be provided.

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 names the specific operation (change/move) and resource (chapter), and lists the exact mutable attributes (title, timecode). This clearly distinguishes it from sibling tools like add_chapter, delete_chapter, and list_chapters.

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?

The intended scenario is implied: use this to modify an existing chapter. No explicit when-to-use, when-not-to-use, or alternative tools are named, though the sibling names make the distinction inferable.

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