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

Annotations declare destructiveHint=true and readOnlyHint=false, and the description adds real behavioral context beyond them: the call is credit-free and returns the updated item. It also discloses a subtle persistence rule (manual pillar/funnel assignments survive automatic tagging). It does not, however, address the destructive flag directly — whether replacing `text` discards the previous version is left unexplained.

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 tight sentences: what it edits, how to use it plus the sibling redirect, and the return/cost facts. The editable-field list is front-loaded and the exclusion follows immediately; nothing is redundant.

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 9 parameters, full schema coverage and no output schema, the description covers the field scope, the draft-vs-saved routing, the return value and credit cost. The remaining gap is the destructive semantics — an agent still cannot tell whether overwriting text or clearing pillar_id/funnel_stage is reversible.

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 the baseline is 3. The description exceeds that by explaining the persistence semantics of pillar_id and funnel_stage ("a pillar or funnel stage set here stays"), which the schema does not say, and by clarifying the status vocabulary in prose. Other parameters are left to the schema, which is fair given full coverage.

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?

Names a specific verb ("Edits") and resource ("a saved library item") and enumerates exactly which fields are editable: title, text, hook, CTA, notes, status, pillar, funnel stage. It also explicitly separates itself from update_draft, so an agent can distinguish it from the closest sibling without opening a schema.

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 a positive usage frame ("Use it to plan and track saved pieces") and an explicit exclusion with the alternative named ("For unsaved drafts use update_draft"). That is both when-to-use and when-not-to-use guidance in one line.

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