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

With no annotations, the description carries the full load and does so well: it discloses idempotency (returns the existing item with created=false), note-replacement semantics on duplicates, the non-permanent nature of filing, the cost profile (free), the REST equivalent (POST /v1/folders/{folder_id}/items), and every error code (404 find_not_found/hook_not_found, 422 kind_mismatch, 409 folder_full with the 2000-item cap).

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?

Front-loaded with the core action and the type pairing, and every sentence contributes (idempotency, note behavior, endpoint, errors). The prose is dense and somewhat run-on with line breaks in odd places, but nothing is redundant or padded.

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?

An output schema exists, so return-value explanation is unnecessary; the description instead covers the gaps that matter — item-kind/folder-kind matching, duplicate handling, persistence semantics, and the full error surface including the folder capacity. Nothing an agent needs to call this correctly 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 83%, so 3 is the baseline; the description still adds real meaning by tying find_id/video_id to long and packaging folders and hook_id to short folders, and by explaining what happens when an id is already filed. It does not explain api_key or the note length limit (the schema does), so it earns a 4 rather than a 5.

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?

States a specific verb (file/save) and resource (a video item into a folder), and immediately scopes the type pairing: find/video_id into long or packaging folders, hook_id into short folders. This lets an agent distinguish it from siblings like edit_folder_item, remove_from_folder, keep_find, and keep_hook without inspecting their schemas.

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?

Explicitly constrains which id goes with which folder kind and even states 'Filing does not keep it', which implicitly routes the agent to keep_find/keep_hook for persistence. It stops short of naming those alternatives or stating exclusions directly, so it falls just below a full 5.

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