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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the mutation profile is covered. The description adds value the annotations cannot: this mutates a chart 'you are building' and feeds a downstream publishing workflow. It does not resolve the tension between the word 'Delete' and destructiveHint=false (permanence, reversibility, or whether the underlying indicator definition survives), which is the one behavioral gap.

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 tight sentences, front-loaded with the action, then the prerequisite, the alternative, and the follow-up. No sentence is filler; the exclusion is placed immediately after the action it disambiguates.

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 single-parameter chart-mutation tool with no output schema, the description covers purpose, prerequisite, alternative, and downstream workflow. It leaves only edge-case behavior (invalid instanceId, whether the removal is reversible, whether chart_state must be re-read afterward) unstated.

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?

One required parameter with 0% schema description coverage, so the description must compensate. 'Use chart_state to find its instance id' tells the agent exactly how to obtain a valid instanceId, which the schema does not; it stops short of documenting the id's format or behavior on an invalid id.

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: 'Delete an indicator instance from the chart.' It explicitly distinguishes itself from the two nearest siblings, chart_toggle_indicator (hide) and by implication chart_add_indicator, so an agent can pick it 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 the lookup prerequisite ('Use chart_state to find its instance id'), names the alternative for the near-miss case ('To temporarily hide it instead, use chart_toggle_indicator'), and states the follow-up flow (chart_link, or analysis_prepare for a draft needing review). When-to-use, when-not-to-use, and alternatives are all present.

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