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

Annotations establish mutation (readOnlyHint=false), open-world reach, and non-idempotency, and the description adds the concrete effects beyond them: live calls store a subscription, send a confirmation email and notify the team. It also discloses the retry contract for idempotencyKey (reuse with identical input within 7 days, never retry an uncertain action with a new key), which is exactly the side-effect detail an agent needs.

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?

Four sentences, front-loaded with purpose, then validation, live effects and retry semantics in a logical order. Dense but every clause is actionable; no filler.

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 10-parameter, non-idempotent mutation with no output schema, it covers the critical unknowns: dry-run verification, live side effects, consent/approval gating and retry safety. Return values are rightly omitted (no output schema), though failure behavior and the confirmed/whatsapp fields remain unaddressed.

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 40% (<50%), so the description must compensate. It does map 'format, frequency and language' to deliveryFormat/cadence/locale and reinforces dryRun and idempotencyKey, but it says nothing about whatsapp, name/email constraints, or the confirmed gate, leaving part of the low-coverage gap unfilled.

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 and resource ('Subscribe a person to The Pulse by email') and names the essential qualifiers (consent, format, frequency, language). It is clearly distinguishable from the read/search/inquiry siblings, which either retrieve data or capture a non-consented contact.

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 explicit sequencing guidance ('Validate with dryRun:true first') and the condition for a live call (approved submission). It does not name sibling alternatives, e.g. routing a non-consenting inquiry to submit_inquiry, but the consent condition is stated well enough to select the right tool.

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