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

Annotations already declare a non-read-only, idempotent, non-destructive, closed-world mutation, so the "WRITE tool" label adds little. The genuine additions are the plan gate (Indie/Agency, trial counts) and the write-scope auth requirement, which are valuable; missing is behavior on failure, whether retry is only valid for failed/partial items, and any rate limits.

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 compact sentences: the action first, prerequisites second. No filler, though the em-dash and parenthetical phrasing is slightly dense; it could front-load the item scope more explicitly.

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 3-parameter, fully documented mutation with no output schema, the description covers action, plan tier, and auth scope adequately. It leaves out error/not-found behavior and whether a successful call returns the updated item, which are minor given the small surface.

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 each parameter already carries its own description, including 'null clears it' and what `retry` re-queues. The description's 'set or clear' and 'retry its media download' restate the schema rather than adding format or edge-case detail, so 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?

The description uses a specific verb phrase and resource: sets or clears a saved ad's note and re-queues its media download. That is clearly distinguishable from sibling mutators like sonar_ad_spy_vault_save and sonar_ad_spy_vault_remove by effect, even though it doesn't name them.

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?

It states the two supported actions (edit note, retry download) and the plan/auth prerequisites, which implies when to reach for it. However, it never tells the agent when NOT to use it or which sibling to pick instead (e.g., vault_save for a new item, update_keyword_note for keyword notes).

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