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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description adds real behavioral detail beyond them: content is bounded to the episode, and a spoiler notice is prepended when up_to_episode precedes number. It does not describe failure modes for invalid series_id or episode number.

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 that front-load the return format and contents, then the spoiler rule. The long parenthetical content list is dense but each item meaningfully scopes the payload.

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?

With no output schema, the description correctly takes on the burden of describing the return shape (Markdown with speaker-tagged dialogue, narration, artwork descriptions, synopsis, cast, takeaways) and the conditional spoiler prefix. Only error/edge-case behavior is missing.

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 coverage is 100% and all three parameters are self-documented, so the baseline is 3. The description adds only a small increment, restating the up_to_episode spoiler semantics already described in the schema; it gives no format hints for series_id.

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?

Specific verb (returns) and resource (the episode body as Markdown), plus an explicit enumeration of what the body contains (dialogue with speakers, narration, in-world text, art descriptions, synopsis, characters, takeaways). It is clearly distinguishable from siblings like get_glossary or list_episodes, though it never names them.

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?

Implies usage via '中身はその話' (scope limited to that episode) and explains the spoiler-handling behavior of up_to_episode, but never states when to pick this tool over get_context or get_glossary, nor any preconditions for series_id/number.

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