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

Annotations mark this as a non-read-only, non-destructive write, and the description adds genuinely useful context beyond them: the change is forward-looking only, pre-existing scheduled entries are untouched, and undo:true reverses it. The reversibility detail matters because idempotentHint=false could otherwise read as irreversible. It does not contradict any annotation.

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, then the scope constraint, the escape hatch, and the parameter rule. No filler and nothing repeated from the schema.

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 no output schema and half the parameters undocumented structurally, the description carries the important behavioral load well — effect scope, reversal, and the exclusive-or parameter rule. Minor gap: it does not say what happens if neither or both of topic/keyword are supplied beyond the stated constraint.

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 only 50% (site and topic documented, keyword and undo bare), so the description must compensate — and it does: it clarifies that keyword is the single-keyword alternative to topic, that undo:true restores the exclusion, and that exactly one of topic/keyword may be supplied. Site semantics are left to the schema.

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 ('exclude'/'tell the planner never to schedule') plus the two resource types it accepts (topic, keyword), with the exclusivity rule stated. It is clearly distinguishable from siblings like exclude_keyword, dismiss_topic, and remove_plan_entry.

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 effect scope ('only affects future generation') and names the alternative for already-scheduled entries: remove_plan_entry. It also gives the undo path. What it does not do is explain when to prefer this over its sibling exclude_keyword, leaving the topic-vs-keyword sibling routing implied rather than stated.

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