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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description adds value by disclosing that images are stamped with source, capture time, expiry, and warnings, and that temporary files are deleted before the response. This is useful behavioral context beyond the structured 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?

Three concise sentences, front-loaded with the core purpose, followed by two behaviorally important details. No filler or repetition.

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 nine parameters, zero schema descriptions, and no parameter guidance in the description, an agent cannot reliably determine how to supply the snapshot or set fields like 'rights_confirmed' and 'source_format'. The output schema may cover return values, but input semantics are under-specified.

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 0%, so the description must compensate, but it only hints at snapshot-related parameters. It does not explain required 'symbol', optional 'expiry', 'data_source', 'source_data', 'source_format', 'rights_confirmed', or how they relate to the snapshot input.

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 ('Create') and resource ('opaque market and Greek PNG images'), and scopes it to a 'user-supplied snapshot.' This distinguishes it from generic plotting siblings like option_plots, though it never names the sibling explicitly.

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 phrase 'from a user-supplied snapshot' implies the tool should be used when snapshot data is already available, but there is no explicit when-to-use/when-not-to-use guidance or reference to alternatives such as option_plots or option_import_snapshot.

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