mark_watched

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

With no annotations, the description must carry behavioral disclosure. It does reveal the 20-second serialization lock, the placeholder handling for 'long ago', and the anime envelope rule. However, it omits whether the operation is destructive, requires auth, or is reversible, leaving gaps for a mutation tool.

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?

The description is compact and front-loaded with a clear purpose sentence, then structured details. Each sentence adds value—format, type rules, and batching advice—with no fluff. It's slightly dense but efficient.

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?

Given the minimal schema and lack of annotations, the description covers the essential input format, special cases, and operational constraints. An output schema exists, so return format is covered. It could mention error handling or overwrite behavior, but the core usage is adequately specified.

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 0% and the description fully compensates. It explains type values (movie, tv, anime), the items array structure with ids and watched_at, and the 1970-01-01T00:00:01Z placeholder. This adds substantial meaning beyond the bare schema.

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 states a clear action (record watched titles) with a specific resource (user's watch history). It's not a tautology and is distinguishable from siblings like set_status or rate, though it doesn't explicitly contrast 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?

The description provides no guidance on when to use this tool versus alternatives. It only gives operational details (format, batching) and never mentions exclusions or comparisons to sibling tools like set_status or remove_from_history.

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