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

With no annotations, the description carries the full burden and does so well: it declares the login requirement, that deletion removes the storage object and is unrecoverable, and the permission model by role. It also documents the two-step preview/confirm safeguard via previewHash. It stops short of describing pacing, limits, or what the preview response contains beyond 'activity, exact file, visibility'.

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 most important constraint (login/irreversible), then the procedure, then permissions, then the alternative. Very dense semicolon-separated Chinese; every clause is informative, though the packing into one block makes it slightly harder to scan.

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?

No output schema, no annotations, and 0% schema description coverage, so the description had to supply the safety and workflow context — and it does, including irreversibility and the consent gate. It could go further by clarifying the preview payoff and expected IDs, but it is sufficient to call the tool correctly.

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%, so the description must compensate, and it explains the two non-obvious parameters: preview defaults to true and previewHash is required when preview=false. activityRef and materialId are only implicitly covered ('activity, exact file'), with no format note such as the 64-hex hash pattern or ID length, leaving a small gap.

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 and resource (delete activity material / own photo) and adds the scope boundary: organizers delete materials, attendees only their own photos for this event. It also names the sibling it is not (update_activity_material for visibility-only changes), so an agent can distinguish it without opening the schema.

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?

Gives an explicit operating procedure: call with default preview=true first, then repeat the same params plus previewHash and preview=false only after the user explicitly consents. It also names the alternative path (update_activity_material) for the visibility-only case, leaving little to inference.

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