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

Annotations declare readOnlyHint=true and openWorldHint=true, but the description adds valuable behavioral context: it specifies that the tool returns chart specifications (not actual rendered images) for various formats, and explains normalization behavior. No contradictions with annotations.

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?

The description is two sentences, front-loaded with the core purpose and formats, then a second sentence adding key parameter context. No unnecessary words; 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?

Given 8 parameters, full schema coverage, and an output schema, the description covers the main points (formats, normalization). It does not detail all parameters, but those are documented in the schema. The presence of an output schema reduces the need to describe return values. Slight gap in explaining kind and metric defaults, but overall sufficient.

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 description coverage is 100%, so baseline is 3. The description adds meaning beyond the schema by clarifying normalization (per 1,000 residents or per US$1bn GDP) and implicitly explaining the role parameter (asylum vs. origin). This adds value.

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 uses a specific verb 'render' and clearly identifies the resource as 'displacement metric for one or more countries as a chart specification'. It lists four distinct output formats, distinguishing this chart tool from sibling tools like generate_map or country_profile.

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?

The description explains what the tool does and mentions format and normalization options, but does not explicitly state when to use this tool versus alternatives such as compare_countries, trend_analysis, or generate_map. Usage context is implied but not articulated.

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