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

Annotations already flag destructive=true and idempotent=true; the description adds value by scoping the destruction ('Other blocks are preserved'), imposing an optimistic-concurrency prerequisite ('Requires current revision'), and clarifying that this does not launch the test.

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?

Four short, front-loaded sentences with no filler; the core add/replace semantics come first, followed by mode selection, preservation guarantee, and constraints.

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?

An output schema exists, so return values need no explanation. For a mutation with revision requirements, the description covers safety scope, prerequisites, and side effects, though it omits guidance on how the questions payload is validated.

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 carry parameter meaning. It usefully explains blockId (new vs existing) and expectedRevision (must be current), but says nothing about testId or the structure/limits of the questions array (e.g., max 10 items, per-type fields), leaving half the parameters undocumented.

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 ('Add or replace a Survey block's questions') and immediately disambiguates the two modes via blockId semantics. An agent can distinguish append-vs-edit behavior from the description alone, without needing the sibling list.

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 explicit operating conditions: use a new blockId to append, an existing Survey ID to edit, and it requires the current revision and does not launch. It stops short of naming a sibling alternative, but the when/when-not is clear.

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