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

Annotations already declare readOnly/openWorld=false, and the description adds meaningful context beyond them: data is stored rather than live, a null result means insufficient history rather than error, and no prediction is made. Return shape of the historical series is not described.

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 short sentences, front-loaded with what is read, followed by the empty-result semantics and the key caveat. 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?

Covers storage scope and the null-result meaning, which are the critical behaviors, but with no output schema the description should hint at what the returned insight/series contains. Parameter-level details are also unaddressed.

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%, and the description only clarifies that the date is a single departure day and that a single adult is assumed. It says nothing about origin/destination format, the cabin default, or why the cabin enum matters.

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 concrete verb and resource: reads a stored price assessment and historical series for a specific departure day and one adult. The phrase 'not a live fare' implicitly separates it from search_flights_live, though it never names that sibling.

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?

It clarifies what the tool is not (live fare, prediction) and explains the missing-result case, which implies when to rely on it. There is no explicit 'use this instead of search_flights_live when...' routing statement, leaving the alternative to inference.

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