Update DataLens QL chart

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

The description adds real value beyond the annotations by disclosing that no revision check occurs and that a save overwrites whatever was written since the last read, i.e., a lost-update hazard. This goes meaningfully further than the idempotentHint/destructiveHint flags, and it also comments on the reply. It stops short of describing mode behavior (save vs publish), which the schema covers.

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 tight sentences: the action comes first and the concurrency caveat second. Phrasing like "as it came" and "(measured)" is slightly cryptic, but nothing is wasted and it is front-loaded.

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 mutation tool with full annotation coverage, a fully described schema, and no output schema, the description supplies the critical missing piece: the lack of revision checking and the resulting overwrite risk, plus a note on the reply. An agent has what it needs to call this safely.

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 100%, so the parameters (entry_id, template, mode, data, annotation) are already documented in the schema. The description adds no parameter-level meaning, so the baseline of 3 is appropriate.

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?

The description states a specific verb ("Save") and resource ("a QL chart") that matches the name, and clarifies it writes the chart "as given". It does not explicitly differentiate itself from datalens_charts_ql_create or datalens_charts_ql_get, but the save/overwrite framing is clear enough to distinguish a write from the get/create siblings.

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?

No when-to-use guidance or named alternatives are given; the reader must infer that this is for persisting changes to an existing chart. The only contextual note is a concurrency caveat, which is behavioral rather than usage-routing information.

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