get_arcRetrieve canon One Piece arc details—saga, position, chapter/episode ranges, release years, and neighboring arcs—from partial names like 'wano'.
A canon story arc's saga, position in the story, chapter/episode/volume ranges, release years and neighbouring arcs. Accepts loose names such as 'wano' or 'Enies Lobby'.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Arc name, e.g. 'Marineford' or 'Whole Cake Island Arc' |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnly/openWorld/idempotent signals, so the burden is lower. The description adds genuinely useful behavioral detail beyond those annotations: loose/fuzzy name matching ('wano') and the canon-only scope. It does not describe ambiguity or no-match behavior, but the added context is meaningful.
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?
Two compact sentences, zero filler. The output scope is front-loaded, and the loose-name usage note follows immediately. Every word contributes useful information.
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 single-parameter, read-only tool this is largely complete: purpose, accepted input behavior, and return topics are covered. Since there is no output schema, the description's field list serves as the return contract, but it does not spell out exact response shape or failure/ambiguous-match behavior.
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?
With 100% schema description coverage, the baseline is 3. The description adds value by disclosing that loose, partial names are accepted and gives concrete examples ('wano', 'Enies Lobby') that the schema does not imply. This lifts it above baseline.
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 names the resource (canon story arc) and the specific output fields it provides (saga, position, ranges, release years, neighboring arcs). It is slightly elliptical—no explicit verb—but the name and title make the action unambiguous, and it is easily distinguished from sibling tools like get_chapter and list_arcs.
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 note about accepting loose names is helpful input guidance, and it implies this tool is for looking up arcs by name. However, it never explicitly contrasts this with siblings like list_arcs, get_chapter, or search_wiki, nor does it state when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.