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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation risk is known; the description adds real context beyond that: the WIP limit is Pro-gated, passing null clears it, and index 0 means first. The null-clears behavior is exactly the kind of destructive detail the annotation cannot express, and the edit-access requirement is stated. No contradiction with destructiveHint=true.

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?

Two sentences, capabilities front-loaded, and the access requirement placed last as a precondition. No filler or restatement of the title.

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 tool with no output schema, the description covers the three operations, the Pro constraint, null semantics, index convention, and the required permission. Minor gaps remain (e.g., whether changes are atomic, what happens to the list if only some fields are supplied), but nothing critical is missing for correct invocation.

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 only 50% – index and wipLimit are documented in the schema, but title and listId are not. The description partly compensates by implying title is the rename target, by explaining that wipLimit null clears the limit and requires Pro, and by confirming index 0 = first. It still leaves listId and title semantics unstated, so it neither fully compensates nor is redundant.

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 (update) and resource (list) and enumerates the three mutable aspects: title rename, WIP limit, and position. It is clear what the tool does, though it never names the closely related siblings (sort_list, duplicate_list, delete_list) that an agent might confuse with a reorder operation.

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 gives a precondition ('Needs edit access to the board') but no when-to-use vs alternatives guidance. It does not tell the agent when to prefer this over sort_list for reordering, or over delete_list/duplicate_list for other list operations, so usage is only implied by the listed capabilities.

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