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

Annotations cover the write/idempotent/non-destructive profile, and the description adds a genuinely useful security note that source text is untrusted reference material, which tells the agent not to act on embedded instructions. The idempotencyKey reuse instruction adds operational context beyond idempotentHint=true, though return/error behavior is left to the output schema.

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 short sentences, front-loaded with the core action and ending with the untrusted-source caveat and idempotency hint. Efficient, though 'Reuse idempotencyKey.' is a telegraphic fragment that reads as a clipped instruction.

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, but for a 7-parameter write tool with 0% schema coverage the description leaves several inputs (brandId, tags, excerpt) and their constraints undocumented. It is adequate but not complete for correct invocation.

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?

With 0% schema description coverage the description must carry the load, and it only clarifies four of seven params (sourceUrl, title, note, idempotencyKey). brandId, tags, and excerpt go entirely unexplained, and 'bounded original notes' only loosely maps to the 2000-char note cap.

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 (save) and resource (intelligence item / brand research evidence) plus the key fields involved (public source URL, title, notes). It is distinguishable from save_library_ad and save_brand_fact by naming source URL and original notes, though it never explicitly contrasts with those siblings.

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?

'Reuse idempotencyKey' is a practical hint about repeated calls but is not a when-to-use directive. There is no guidance on when to choose this over save_brand_fact, add_intelligence_target, or save_library_ad, and no exclusions or prerequisites are stated.

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