Preview YNAB Assignments

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

The description adds valuable behavior beyond annotations: it reveals the tool creates a 'short-lived preview token' and validates 'freshly', implying live state checks. The 'without changing YNAB' aligns with readOnlyHint=true and destructiveHint=false. No contradictions found. It could further explain token expiry or usage, but the added context is meaningful.

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?

The description is a single, tightly worded sentence that front-loads the action ('Freshly validate') and conveys mode, purpose, and safety in under 20 words. Every phrase earns its place with no redundancy or 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?

Given no output schema, the description hints at the return value ('short-lived preview token') but does not describe its format or how it integrates with sibling tools like ynab_apply_assignment_preview. The complexity is moderate, but the tool's purpose and primary outcome are clear, and the sibling list supplies enough context to infer usage. Slightly more detail on token validity or validation failure would push it to 5.

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 50% (plan_id and guard_month are described; month and assignments are not). The description's reference to 'exact category assignment deltas' clarifies the assignments parameter, and 'validate' implies the tool checks these deltas. However, it does not compensate for all undocumented parameters (e.g., month format or category_id semantics), leaving the schema to carry half the burden.

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 uses specific verbs ('validate', 'create') and a clear resource ('exact category assignment deltas') plus a concrete output ('short-lived preview token'). It explicitly states 'without changing YNAB', distinguishing it from sibling tools like ynab_apply_assignment_preview. This is a precise and unambiguous purpose statement.

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 phrase 'without changing YNAB' implies this is the safe, non-destructive alternative to applying assignments, providing clear context for when to use it. However, it does not explicitly name alternatives or state 'use this when you want to validate before applying', so it stops short of a full when/when-not guide.

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