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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real context beyond that: the license is CC BY 4.0 and, importantly, that this applies to the aggregate numbers, plus the fact that the source photo set is included — licensing scope the agent would otherwise have to assume.

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?

One compact sentence covering the return payload followed by a short usage trigger; no filler. The mixed return-list / usage-instruction structure is slightly compressed but still front-loaded and readable.

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 no output schema and no parameters, the description is the only source for return values, and it does enumerate them (citation text, license, source photo set). What is missing is minor: no note on whether non-aggregate figures carry different licensing, and no routing to sibling tools.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate; the baseline for a zero-parameter tool is 4. The empty schema is consistent with the description, which describes a fixed-content retrieval.

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 names the concrete payload (citation text, license terms, source photo set) for a clearly named retrieval tool, so an agent knows what comes back. It is a content list rather than a verb+resource statement, and it does not explicitly distinguish itself from nearby informational siblings like get_methodology or get_reference_statistics.

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?

"Use when quoting a number" gives one concrete trigger condition, which is better than nothing. However, it names no alternative and gives no exclusion (e.g., what to use instead when you need the methodology behind a number), leaving sibling selection to inference.

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