Character update

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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the bar is lower, and the description still adds real value: it names the write target (local overlay file), guarantees the packaged table is untouched, and gives the cautionary rationale that a wrong alias is worse than a missing one. It omits what happens on an unknown char_id with no name, or whether an overlay file is created if absent.

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 purpose is front-loaded in the first line, followed by motivation and then an Args block, so the agent reads the important content first. The Args block is somewhat verbose relative to an already-titled schema, but each entry adds examples the schema lacks, so little 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 no explanation, and annotations cover read-only/idempotency. For a six-parameter mutation with a local overlay side effect, the description explains the write target and non-destructiveness of the packaged data; the remaining gap is failure behavior (unknown char_id, missing name) and valid server values.

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 0%, so the description carries the full burden, and it documents all six parameters with meaning plus examples (six-digit arena id, Chinese name, alias list, Japanese name, servers, removal list). The gap is `servers`: 'servers the character exists on' gives no valid set of values or enum hint, and it doesn't say whether `name` overwrites an existing entry.

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 first sentence states a specific verb and resource: add a character or extend its aliases in the local overlay file, and explicitly notes that the packaged table is never modified. It contrasts with the read-side siblings (character_lookup, character_match) implicitly through 'overlay file' mutation, but never names character_correct, which is the nearest ambiguous sibling.

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 context is implied by the Japan-first publishing note, which explains why an agent would pass `jp` immediately. However, there is no explicit when-to-use/when-not guidance and no routing to siblings such as character_lookup (read) or character_correct (fix an existing entry), leaving the agent to infer which of the two mutation-ish tools to call.

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