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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the write-but-not-destructive profile is covered. The description adds genuine workflow context that annotations cannot: changes affect the chart being built, and the session should finish with chart_link or analysis_prepare for a human-reviewed draft. It does not disclose whether edits are reversible or overwrite existing params, which keeps it from a 5.

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?

Four front-loaded sentences, each carrying a distinct instruction: purpose, prerequisites, alternatives, and follow-up. No repetition and nothing wasteful.

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?

No output schema exists, and the description covers the full call lifecycle for a low-complexity mutation: how to obtain inputs, the sibling boundary, and the recommended completion step. Nothing required to invoke it correctly is missing.

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 0% and params is an unexplained nested object, so the description must compensate. It does so well by routing to chart_state for the instanceId and catalog_describe for supported parameter shapes, giving an agent a path to the missing semantics even though no inline format is stated.

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+resource ('Edit the parameters of an existing indicator instance') and immediately distinguishes itself from siblings chart_remove_indicator and chart_toggle_indicator by naming what each does instead. An agent can pick the right tool without opening any schema.

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 explicit prerequisites (call chart_state for the instance id, catalog_describe for supported parameters) and names the alternatives for delete and show/hide cases with the condition that selects them. This is a textbook when/when-not routing paragraph.

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