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

Annotations already declare readOnly, idempotent, and non-destructive; the description adds specific behavioral detail by describing the transformation ('converts persisted market-factor history into field pressure...') and explicitly stating what it does NOT do (create factors, reconstruct depth, override rows). This adds substantial context beyond the generic hints.

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 compact and front-loaded. It states the purpose, then the process, then parameters, then behavior, without redundant or unnecessary sentences. Every phrase adds value.

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 the output schema exists, return values need not be described. The description covers purpose, transformation, parameter summary, and limitations (read-only, no side effects). It is complete for an agent to select and invoke the tool correctly.

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?

All 6 parameters have detailed schema descriptions, so the baseline is 3. The description adds a useful clarification that source_date is an alternative to source_date_from/source_date_to, implying mutual exclusivity, which is not explicitly stated in the schema. This small addition justifies a 4.

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 clearly states a specific action ('retrieve the market SPECTRA field map') and a specific resource ('one Coinbase INTX perp product'). It distinguishes from siblings by emphasizing the Coinbase perp-focused scope and the conversion process into labels.

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 opening 'Use this read-only tool to...' provides clear context for when to use it. It also includes exclusions via 'does not create factors, reconstruct missing depth, or override the underlying factor rows,' but it does not explicitly name alternative tools or contrast with siblings.

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