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

Annotations already declare this is a write (readOnlyHint=false), non-idempotent, non-destructive. The description adds real behavioral context beyond them: "Creates the peers on first use" discloses a side effect (peer creation) an agent could not infer otherwise.

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?

Two tight sentences, front-loaded with the purpose and followed by concrete examples and formatting guidance. No filler; the examples earn their space by clarifying what counts as a fact.

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?

An output schema exists, so return values need no explanation. The description covers purpose, content format, and the peer-creation side effect, and the schema covers the optional session/workspace/peer parameters; only explicit sibling routing is absent.

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 all five parameters are already documented, making 3 the baseline. The description adds a little meaning — each conclusion should be a "short, self-contained statement" — but this is content-format advice rather than parameter clarification.

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 and resource ("Save facts") with a concrete scope constraint ("facts you were told outright") and examples. It does not explicitly distinguish itself from siblings like add_messages_to_session or list_conclusions, so a 4 rather than 5.

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?

Provides an implicit trigger — facts the user stated outright, as opposed to inferring them — and hints at timing ("so memory has them straight away"). However, it names no alternative tool and gives no explicit when-not-to-use guidance.

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