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

Annotations already cover read-only, idempotent, open-world, non-destructive. The description adds meaningful behavior beyond that: missing compared months yield reported:false and are excluded from ranking rather than zero-filled, and the tool is keyless. That exclusion rule is exactly the kind of subtle behavior an agent needs and cannot infer from 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?

Front-loads the core comparison semantics, then supplies defaults, the missing-month rule, and a compact example. Every sentence carries information; nothing is boilerplate.

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?

No output schema exists, yet the description explains the return semantics (ranked by change, reported:false flagging, exclusion rule), the defaults for all optional params, and the keyless access model. An agent has what it needs to call and interpret the result.

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 all four parameters (flow, countries, end_month, months_back) are already documented in the schema. The description reinforces the months_back=12 YoY vs 3 QoQ semantics and the Gulf default via its example, but adds little the schema does not already carry.

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 (compare) and resource (JODI-Gas countries on one series) with the ranking behavior and time-over-time comparison made explicit. It is clearly distinguishable from siblings like jodi_gas_series (raw series) and jodi_oil_compare (different dataset).

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?

Gives concrete triggering questions ('which Gulf gas producers grew LNG exports most', 'Qatar gas production vs last year') and states default behavior when no countries are supplied. It stops short of explicitly naming when to use jodi_gas_series instead, but the comparison framing makes the boundary fairly clear.

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