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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description correctly spends its words elsewhere: it discloses the spoiler-marking rule, the omission behavior tied to up_to_episode, and that source URLs are present only for some entries. That is real behavioral context an agent could not derive from the annotations. It stops short of describing ordering or entry count, which keeps it at 4 rather than 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?

Purpose and return contents are front-loaded, then sibling routing, then the parameter behavior — a logical order with no filler sentences. It runs somewhat long and the get_episode/search_works routing plus the up_to_episode rule partially duplicate the schema, but every clause carries usable 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?

There is no output schema, so the description carries the burden of describing the return shape, and it does: explanation text, in-world vs real-world distinction, conditional source URLs, episode numbers, and spoiler flags. Combined with the spoiler-filtering semantics and sibling routing, an agent has enough to call it correctly. Ordering and result-size expectations are the only omissions.

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 both parameters are already documented, and the description largely restates the schema's own wording for up_to_episode (omit later-episode terms; default returns everything with a spoiler mark from episode 2 on). It reinforces intent (avoiding spoilers for what the user has read) but adds no syntax, format, or edge-case detail 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?

The description opens with a specific verb + resource ("作品の用語集を返す") and then enumerates exactly what a term entry contains: a short explanation, an in-world-vs-real-world flag, source URLs where available, and the episode number. It explicitly distinguishes itself from get_episode (scene context) and search_works (finding the series), so an agent can tell the three apart without opening any 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?

It names both alternatives and the condition that selects them ("漫画の場面でどう出てくるかは get_episode", "どの作品の用語かは search_works"), and it spells out the when/when-not for up_to_episode: pass it to suppress later-episode terms, omit it to get everything with spoiler marks. Nothing about tool selection is left to inference.

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