getPythHistoricalPrice

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

With no annotations, the description carries the full burden. The verb 'fetches' implies a read-only operation, but it does not disclose potential errors, return format, or any edge-case behavior. It adds minimal context beyond what the name already implies.

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?

A single, front-loaded sentence with no wasted words. It conveys the essential information efficiently.

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?

For a simple two-parameter historical price fetch, the description is adequate. While no output schema exists, the return type (price) is strongly implied by the tool name and description. The differentiation from siblings is clear via the 'Historical' qualifier in the name.

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 coverage is 100%, so the baseline is 3. The description's mention of 'unix timestamp (seconds)' is redundant with the schema's 'Unix timestamp in seconds', adding little value. It does reinforce the 'as of' relationship, but not enough to exceed the baseline.

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 the tool fetches Pyth's price at a specific unix timestamp, using a specific verb ('fetches') and resource. It distinguishes itself from siblings like getPythPrice by explicitly mentioning the historical aspect.

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 context is clear: this is for historical prices at a given timestamp, which inherently contrasts with getPythPrice (current price). However, it does not explicitly name alternatives or exclusions, so it stops short of a full 5.

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