add-to-album

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

With no annotations, the description fully bears the transparency burden. It discloses that it is a WRITE tool requiring an environment variable, that it is idempotent (alreadyPresent field), imposes a 100-UUID limit, validates photo existence, and drives AppleScript (launching Photos.app and requiring permission). This is unusually thorough.

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 well-structured with clear sections ('Use when', 'Returns', 'Do not use when', 'Safety'). It is front-loaded and every sentence adds information. However, it is somewhat lengthy and could be slightly more concise without losing clarity.

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 tool's complexity (write operation, idempotency, error conditions, sibling differentiation), the description covers all essential aspects: prerequisites, failure modes, safety requirements, and output fields. The presence of an output schema further reduces the need for detailed return description, but the description already lists key return fields.

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 100%, so baseline is 3. The description adds value by revealing the typical source of UUIDs ('from query / find-duplicates') and clarifying that the album parameter accepts both name and UUID. This slight augmentation justifies a 4.

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 clearly states the tool's purpose: adding photo UUIDs to an album. It provides specific use cases (e.g., collecting duplicate extras, filing trip photos) and distinguishes itself from siblings by explicitly contrasting with remove-from-album and create-album.

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 explicit guidance: 'Use when: you have photo UUIDs... and want to file them into an album.' It also gives clear when-not-to-use instructions, directing the agent to create-album for missing albums and remove-from-album for removal tasks. This covers both context and alternatives.

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