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

Annotations only say it is a non-read-only, idempotent, non-destructive write; the description goes well beyond that by disclosing the cascade of side effects (cancelling pending drafts and open follow-up tasks, halting future drafts) and the required write_crm scope. That is exactly the information an agent needs before committing an irreversible state transition.

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?

A single tight sentence that front-loads the action and then the consequences; every clause carries new information (state change, cancellations, draft suppression, scope requirement). No filler or restatement of the title.

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, the description does not say what the call returns (e.g. the updated contact or counts of cancelled drafts/tasks), which would help an agent verify success. Everything else — trigger, effects, permissions, idempotency — is covered, so the gap is minor.

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 all five parameters (including idempotency_key semantics) are already documented in the schema. The description adds only the framing that reply text is optional, which is already implied by the absence of required parameters — 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?

States a specific verb and resource ('Record that a contact replied') and immediately enumerates the concrete state changes: contact set to replied, drafts and open follow-up tasks cancelled, further drafts stopped. This distinguishes it from read-side siblings like list_replies and from add_note, which merely attaches content without changing enrollment state.

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 a clear triggering condition (a contact replied) and a prerequisite ('Requires the write_crm scope'), plus notes the reply text is optional. It stops short of naming alternatives — e.g. when to use add_note instead, or whether list_replies must be checked first — so no exclusions are provided.

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