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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real behavioral content beyond that: it describes what the manual holds (fact counts, sources) and prescribes that the agent should follow it, which with no output schema is valuable.

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 dense sentence, front-loaded with the resource and ending with the imperative ordering rule. The em-dash asides are slightly convoluted but earn their place; 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?

For a one-optional-param, read-only tool with no output schema, the description covers purpose, content, and usage timing adequately. It could do a bit more to contrast with listFacts/getStep for the fact-related content, but nothing essential is missing.

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% and the 'store' parameter is richly documented in the schema itself (link formats and the default FactoGraph-guide behavior). The description adds no parameter-level meaning, so baseline 3 is appropriate.

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+resource ('The store's manual') and enumerates what it contains ('how to run its steps and cite its facts', 'how many facts, from which sources'). It is clearly distinguishable from data-oriented siblings like listFacts or getStep, though it doesn't name them 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?

Gives explicit ordering guidance: 'Read it before the store's other tools, and follow it.' This tells the agent when to reach for this tool relative to all siblings. It stops short of a when-not or naming a specific alternative, so it is not a full 5.

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