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

The description adds substantial context beyond the annotations: it discloses cost (no credits), that nothing is generated, that existing filmed episodes are not retroactively changed, and it describes the three returned fields including the instruction to post 'say' as is. The only mild tension is with destructiveHint=true, since the text emphasizes preservation of existing captions, but it still describes a real settings mutation and does not claim to be read-only.

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?

It front-loads the cost and side-effect facts before the semantic explanation, which is the right order for an agent skimming. The prose is dense and occasionally run-on with quoted field names, but nearly every clause carries operational 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 two-parameter mutation tool with no output schema, the description covers cost, scope of effect, value semantics, downstream script requirement, and the return fields. An agent could invoke it correctly without opening the schema; the only gap is any permission or failure 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?

Schema description coverage is 0%, so the description must carry parameter meaning, and it does for the key parameter: 'language' is a code such as he, ar, en, es (any filmed language, Hebrew and Yiddish included) or empty for dialogue-language captions. series_id is not explained, but it is self-evident from the required-parameter shape.

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 a precise verb and resource: it sets the language of a series' burned captions, with a concrete explanation of what the value means (subtitles under dialogue, or empty for dialogue-language captions). It also distinguishes this effect from sibling save_episode_script, which is named as the tool that flags lines missing a subtitle field.

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 gives clear context for when the setting matters: episodes already filmed keep their captions, while every line of a script filmed from now on needs a subtitle field in that language. It does not state explicit exclusions or name a competing tool for the same job, but the usage condition is unambiguous.

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