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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the vault scope and output style but does not disclose pagination, ordering, or limits; for a simple list tool this is adequate but not rich.

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?

A single sentence with no filler, front-loading the action, scope, and output. Every word contributes meaningful information, and the structure is immediately scannable.

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 one-parameter, read-only list operation with annotations covering safety, the description plus schema is sufficient for correct invocation. It could state the default when type is omitted or note pagination behavior, but these are minor gaps given the tool's simplicity.

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 100%, including the optional type enum with its own description, so the baseline of 3 applies. The description's mention of images and videos aligns with the type filter but adds no behavioral detail such as default behavior when type is omitted.

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 action ('List') and resource ('images and videos in the user's vault'), and signals the output form ('summaries and metadata'). This makes it distinguishable from siblings like semantic_search_media, which implies relevance-based retrieval, and get_media_description, which targets a single item.

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 implies usage as a listing/inventory tool but gives no explicit when-to-use guidance or alternatives. An agent must infer from sibling names that semantic_search_media is the search counterpart, so clear context exists but exclusions are absent.

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