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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds useful context about what content is surfaced, but says nothing about behavior beyond content — e.g. what happens if chart_id is omitted, whether missing citations error, or any caching/rate behavior.

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?

Two tight sentences, front-loaded with the core retrieval scope and then the optional extension. No filler or restated title.

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?

With an output schema present, return values need no explanation, yet the description still helpfully previews them. The chart_id linkage to list_charts is present; only the absent 'when vs get_chart_data' routing keeps it from being fully complete.

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 100%, so chart_id's enum is fully documented there (baseline 3). The description adds real meaning by clarifying the parameter is optional and that supplying it widens the response to chart-specific comparison, period and population.

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 ('Retrieve') and resource ('citation') and enumerates the content returned (source, canonical URL, dates, methodology, interpretation limits, reuse terms). This distinguishes it from get_chart_data/list_charts by implication, though neither sibling is named.

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?

Usage is only implied: the second sentence signals the optional chart-specific mode, and the schema notes chart_id comes from list_charts. There is no explicit 'use this when you need attribution/provenance rather than the data values' statement or named alternative.

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