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

Annotations already establish the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower; the description still adds real context by disclosing the return payload (component observations, absolute/percent changes, CAGR, units, vintage evidence, caveats) and the temporal-safety role of as_of_year. This goes beyond what the annotations convey.

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, front-loaded with the core verb and resource, then returns, then use cases and the as-of caveat. Every sentence carries distinct information with no filler.

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, the description usefully enumerates what comes back, covers all four parameters, and supplies invocation examples, making it largely self-sufficient. The one gap is sibling routing: an agent choosing between this and bea_state_economic_history gets no explicit guidance.

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 earns an extra point by explaining the semantic intent of as_of_year ('prevents future observations from entering a historical calculation'), which the schema only weakly hints at. It adds no syntax beyond the schema for the other three parameters.

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+resource ('Calculate prior-observation and exact five-year changes for one official BEA SASUMMARY state indicator') and enumerates the returned components, so the agent knows exactly what computation this performs. It does not name the adjacent siblings (bea_state_economic_history, bea_state_economic_profile, bea_compare_states), so differentiation is left to inference from the 'trend/change' framing.

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?

Three concrete invocation examples ('five-year Florida GDP trend', 'how has Ohio employment changed?', 'California real per-capita income growth') give clear context for when this tool applies. It stops short of stating when NOT to use it or naming an alternative sibling for profile/history lookups.

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