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

With no annotations supplied, the description carries the full burden and does so: real side effects, non-idempotent, runs the server-saved version pinned to versionId, triggers return immediately without polling, and blocks reading upstream results see only previously test-run data. It also discloses the ~24 s polling ceiling, the completed: false fallback state, and that retrying re-runs the block rather than resuming.

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?

Semantically dense and front-loaded with the side-effect warning first, which is the right ordering. It is a long run of semicolon-joined clauses packed into one paragraph, so the rejection list and the polling caveat are harder to scan than they need to be.

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 no-annotation, no-output-schema mutation tool this covers the essentials: side effects, idempotency, eligibility rules, upstream-data dependency, and timeout behavior. It stops short of describing what the return payload contains beyond the completed flag, or what permissions the caller needs.

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% across three required parameters, so the description must compensate. It adds real meaning for versionId (the version saved server-side is what executes) and implicitly for nodeId (the block must be issue-free and of an eligible type), but workspaceId is never mentioned and no ID formats or scoping rules are given.

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?

"Execute one saved block now, with real side effects" gives a specific verb (execute), narrows the resource to a single block, and immediately contrasts with whole-flow siblings like start_flow and run_dynamic_tool. The parenthetical examples (sends the email, writes the row, calls the API) make concrete what 'execute' means.

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?

Explicitly routes the agent: triggers only arm themselves and return without polling, repeat/list-iterator/actions-group/triggers-group are rejected and must be test-run at a child, while condition/router/ai-router do execute. It also states the prerequisite that the node must have no issues and that upstream data is only visible if those blocks were test-run earlier.

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