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

Annotations already flag destructiveHint=true and idempotentHint=true, and the description adds real value beyond that: optimistic concurrency via expected_revision, and the explicit boundaries that linking copies no social automation authority and grants no cross-workspace access. It omits what happens to a film already linked to the series and says nothing about reversibility.

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 sentences, no filler, and the authorization caveats are packed efficiently. The first sentence is slightly convoluted ('Change a Series membership using...') when 'links a film into a series' would be more direct.

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?

The output schema means return values don't need explaining, and the concurrency and authorization notes cover the trickiest risks. But a destructive, 4-required-parameter mutation with zero schema descriptions should also cover request_key and what happens to an existing film link.

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. It explains expected_revision ('current series revision') and film_id ('separately authorized Film') in passing, and only implies series_id, while request_key is completely unaddressed and there is no hint about its idempotency or deduplication role.

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 gives a clear operation ('Change a Series membership') with the mechanism (current series revision plus a separately authorized Film), which is enough to identify the action. It never names the sibling unlink_series_film, so an agent must infer from the title that this adds rather than removes a link.

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?

Use is implied by the wording: it needs an up-to-date series revision and an independently authorized film, hinting at a concurrency precondition. There is no explicit when-to-use/When-not guidance and no mention of unlink_series_film as the counter-operation.

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