Attach a fact to a node

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

Annotations already declare readOnly=false, destructive=false, idempotent=false and closed-world, so the safety profile is carried by structured data. The description adds real value by stating the note does not mutate node state or the stack, and that the response flags a node accumulating notes with nothing filed under it. It stops short of describing return format or duplicate-note handling, which the non-idempotent hint makes relevant.

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?

Front-loads the core action and the state-preservation constraint, then spends the remainder on exclusion rules and a feedback behavior. The middle sentence is dense and comma-heavy but every clause carries routing information. Minor trim possible but nothing is 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?

With no output schema, the description does mention that the answer reports a node collecting notes without filed children, partially covering return behavior. Combined with the annotation-provided safety profile and full schema coverage, an agent has enough to call it correctly; only explicit return/pagination detail 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 description coverage is 100%, so both parameters (id defaulting to current focus, note as the fact) are fully documented structurally. The description adds only loose semantics about what content qualifies as a note, no format or length guidance. Baseline 3 applies.

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 ('attach a fact to a node') plus a scoping constraint ('without changing its state or the stack'). It actively distinguishes itself from sibling write tools by enumerating what a note is not and naming the siblings that handle those cases.

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?

Explicitly defines the class of content that belongs here (how the work went, external changes like CI/tracker/cloud) and excludes three other classes, routing each to `vivac_add` or `vivac_decide`. This is a clear when/when-not with named alternatives.

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