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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=true, so the description needn't restate the safety profile. What it does add is a persistence rationale (the text will be wanted again later) and a nudge to give a title so it can be recognised. It says nothing about duplicate handling despite idempotentHint=false, nor about permissions or what a successful store returns.

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, with the core action and the concrete examples front-loaded before the usage condition and the title advice. No filler; only mild redundancy between 'wanted again' and 'worth keeping'.

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?

This is a low-complexity three-parameter write tool with full schema coverage and no output schema, so the description carries most of what an agent needs: what to store, when, and how to title it. The main gap is routing against the from_file/from_url variants and the lack of any note on duplicates.

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 the schema already documents all three parameters, giving a baseline of 3. The description adds one useful piece of meaning beyond the schema: although only content is required, a title should still be supplied so the item is recognisable later. It adds nothing for sourceUrl and no format or length guidance.

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?

Specific verb and resource ('Stores text... in the knowledge base' via the title) with concrete examples of what kind of text (product details, positioning, a policy, call notes). It distinguishes the tool from transient conversation use, but never names the close siblings add_knowledge_from_file / add_knowledge_from_url, which an agent could easily confuse with it.

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?

'Use it when the user tells you something factual worth keeping, rather than only using it in this conversation' is a clear and actionable trigger condition. It stops short of explicit exclusions (e.g. when to prefer the from_url/from_file variants or search_knowledge instead), so it is not a full 5.

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