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

With no annotations provided, the description carries the full behavioral burden, and it does this well: it discloses the scheduling engine, the returned artifacts (picture, dates, critical path, link), export/save capabilities, deadline marker semantics, and the instruction to always show the link. The only minor gap is that it does not explicitly state whether or how the chart is persisted server-side.

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?

The description is long but dense and every section earns its place: the core purpose is front-loaded, authoring rules are actionable, and the sibling-tool distinction is at the end. It loses a point only because the 'YOU author the plan' block could be tightened without losing meaning.

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 complex tool with no output schema, the description is remarkably complete: it covers auth, input construction rules, dependency semantics, phase grouping, deadlines, return values, link behavior, exports, and when to choose the alternative tool. An agent has enough context to select and invoke this tool correctly.

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 high at 86%, and the description still adds substantial semantic value: dependencies are 0-based positions of earlier tasks, typed links use { task, type, lag }, independent tasks should run in parallel, phases use isPhase and parent, milestones have duration 0, and deadlines are markers rather than hard constraints. This is far beyond what the schema alone conveys.

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 opens with a specific verb-resource pair: 'Create a Gantt chart from a task list.' It goes beyond a generic creation statement by specifying input (task list), output (chart, dates, critical path, link), and the absence of auth requirements. This clearly separates it from the sibling schedule_project tool.

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 final sentence gives explicit routing guidance: use create_gantt when the user wants a chart to open/export/save, and use schedule_project instead for what-if date math where nothing should be stored. This is concrete, contrastive, and leaves no ambiguity about tool selection.

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