Update DataLens editor chart

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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the bar is lower, and the description still adds real behavior: no revision check, a save silently clobbers anything written since the last read. That concurrency hazard is exactly the kind of context annotations cannot express; the parenthetical '(measured)' is unclear noise.

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 short sentences, with the core action front-loaded and the overwrite caveat immediately after. The trailing '(measured)' is a cryptic, unexplained token that slightly weakens an otherwise tight statement.

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 two-parameter write tool with full schema coverage and annotations covering the safety profile, the description supplies the one missing behavioral fact an agent needs: this save is blind to revisions. It does not mention the save/publish distinction outside the schema or any return information, but neither is essential here.

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% and the schema itself carries the mode semantics ('save keeps a draft; publish makes it the version shown') plus per-field tab descriptions. The description restates the payload as 'entryId, kind, and code', which adds nothing beyond the schema, so the baseline 3 applies.

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 ('Save a chart of the editor'), which is clearly distinct from the create/delete siblings in the datalens_charts_editor_* family. It does not, however, name or route against the neighboring update tools (charts_wizard_update, charts_ql_update), so differentiation relies mostly on the name.

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 implies the tool is for persisting an already-read editor chart and warns about the overwrite condition, which is useful timing context. It never states explicitly when to choose this over create or over the wizard/QL update tools, so usage remains inferred.

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