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

The description states 'Changes the chart you are building,' which reinforces the annotations' readOnlyHint=false and discloses the mutation side effect. It also adds the default-value behavior for omitted params and the linking step, which are useful beyond the schema and annotations. No contradiction with annotations.

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?

Three sentences front-load the core purpose, then add parameter guidance, default behavior, and the chart_link follow-up. Every sentence earns its place and there is no repetition of schema data.

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 mutation tool with no output schema, the description covers invocation, parameter resolution, default behavior, and post-call chart linking. It is complete enough to call safely; a small gap is not describing what happens with an invalid or unrecognized studyId.

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?

With 0% schema description coverage, the description compensates by explaining studyId as an id or common name with concrete examples ('ema20', 'bollinger') and delegating params to catalog_describe for details. It could enumerate params, but it clearly orients the agent on how to populate both fields.

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 action and resource: 'Put an indicator on the chart.' It clearly distinguishes the tool from sibling mutation tools like chart_remove_indicator, chart_toggle_indicator, and chart_update_indicator by describing the add operation.

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?

It gives practical usage context: studyId can be an ID or common name, catalog_describe is the source for parameters, and chart_link should be called when finished so the person can open the chart. It does not explicitly name alternate chart tools, but the workflow around building and sharing a chart is clear.

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