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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so 'Repeating the same membership is safe' largely restates idempotentHint. The genuinely additive parts are the 'private folder' scope and the preview-first recommendation, but nothing is said about permissions, failure modes, or what happens when the target already exists in another folder.

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?

Three short sentences, front-loaded with the action and cardinality constraint, then the parameter shape, then behavior and workflow. No sentence is redundant.

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 4-parameter mutation with no output schema, the description covers the action, the target union, idempotency and a preview safety path, which is enough to call it correctly. It omits folder ownership or permission requirements and what the caller gets back on a successful add.

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 50%, and the description compensates on the hardest part: it explains the target anyOf union by telling the agent to supply either savedLotId or projectId, which the schema only expresses structurally. It also flags preview=true semantics in-line. It adds no detail on the required 'context' field, but the schema already spells that out at length.

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 with scope: 'Add exactly one saved lot or project to a private folder.' That precisely separates it from createSavedFolder (makes folders), saveLot (saves lots) and removeSavedFolderItem (the inverse), though it names only listSaved explicitly rather than its nearest sibling.

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 a concrete upstream dependency ('savedLotId (a save id from listSaved)') and a recommended workflow ('Use preview=true first'), plus an idempotency note that tells the agent repeats are harmless. It stops short of stating when NOT to use it or naming removeSavedFolderItem as the undo path.

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