chart_set_visible_range

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

With no annotations, the description carries the full burden and does well: it discloses STATE_MUTATING (viewport zoom/pan changes) and the constraint that timestamps must be unix seconds within the historical data range. It omits whether the change is reversible/undoable and how out-of-range input is handled.

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?

Front-loaded with the action, then labeled WHEN TO USE / SIDE EFFECTS / LIMITATIONS sections that are each a single sentence with no filler. The label scaffolding is mildly formulaic but costs little and aids scanning.

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-param mutation tool with no annotations and no output schema, the description covers the essential gaps: effect, trigger, and input constraints. Remaining omissions (failure behavior for out-of-range timestamps, whether the view can be restored) are minor.

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 100% and both params are documented there, so baseline is 3. The description adds genuine meaning beyond the schema by specifying the unit (unix seconds) and the validity constraint (within historical data range), which the schema text does not mention.

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 concrete verb+resource: 'Zoom and pan the chart canvas to display a specific date range.' The mutating counterpart to chart_get_visible_range and chart_scroll_to_date is clear from 'set' + 'zoom and pan', but the description never names those siblings to sharpen the distinction.

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 an explicit trigger ('Call when focusing chart context on a specific historical event or earnings release'), which is real when-to-use guidance. It does not name alternatives (chart_scroll_to_date, chart_get_visible_range) or state when not to use it, so it stops short of a 5.

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