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

Annotations already establish readOnlyHint=false and destructiveHint=false, so mutation is known. The description adds real value beyond that by disclosing the workflow trait: changes affect 'the chart you are building' and are not visible to the person until chart_link is called. It also implies permanence by contrasting deletion with toggling. Minor gap: no statement about revertibility or behavior on invalid instanceId.

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, zero filler. The action is front-loaded, then prerequisite/alternative, then the workflow consequence. Every sentence earns its place.

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 1-parameter, no-output-schema delete tool, it covers the action, parameter source, the key alternative, and the post-condition (chart_link). It does not describe the return value or error behavior, but for a simple chart-mutation tool with annotations covering the safety profile, nothing critical 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%, so the description must compensate for the single parameter. 'Use chart_state to find its instance id' tells the agent where the value comes from and implicitly constrains validity to ids returned by chart_state. It doesn't state the id format, but the provenance hint is meaningful and largely covers the gap.

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?

Starts with a specific verb+resource: 'Delete an indicator instance from the chart.' It differentiates from siblings by explicitly naming chart_toggle_indicator as the temporary-hide alternative and referencing chart_state for id lookup. An agent can clearly tell this from chart_add_indicator, chart_update_indicator, and chart_toggle_indicator.

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?

Provides explicit when/when-not guidance: delete for permanent removal, chart_toggle_indicator for temporary hiding. It also gives the prerequisite (find instance id via chart_state) and the required follow-up (call chart_link when done). This is complete decision-making guidance.

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