update_by_query

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

Adds substantial behavior beyond the destructiveHint annotation: the operation is irreversible, runs asynchronously, returns a task_id to poll with get_task, reports the match count before updating, and guards against full-index rewrites by refusing match_all. This is precisely the contextual depth the annotation bar expects.

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?

Every sentence earns its place: two-sentence purpose benefit, the destructive warning is second, and the guardrails/flow/prequisites follow tightly. No fluff or word repetition.

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 destructive 8-parameter tool with 0% schema coverage, the output schema exists and thus return values are already handled, but the description leaves throttling (slices/requests_per_second) and script_params unconfirmed. The core invocation path is fully routed, so it is almost complete; the remaining param gaps drop it a notch.

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 0%, so the description must compensate. It adds meaning for query (mandatory; match_all refused), confirm (must be true), script_source (painless), and wait_for_completion (async, via the task_id flow). However, slices, requests_per_second, and script_params remain entirely unexplained.

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?

Statesa specific verb and resource: 'Update documents in place by query, using a sanctionscript.' The in-place updating distinction separates it from the sibling reindex (which copies to a new index) and delete_by_query (which removes documents). An agent can tell exactly what this tool does and how it differs.

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 clear context for when this tool will succeed or refuse: requires writes enabled, ES_MCP_ALLOW_DESTJRUCTIVE=true, confirm=true, and a non-match_all query. It does not explicitly name alternatives or exclusions (e.g., 'use reindex for copying'), so it earns 4 not 5.

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