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

Annotations only supply a title and destructiveHint=true, so the description carries most of the behavioral burden. It discloses the channel-dependent identifier rule and the underlying REST endpoint, but says nothing about duplicate handling, idempotency, permission requirements, or side effects — a notable gap for a mutating call flagged as destructive.

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 action and the key semantic rule. The trailing endpoint reference ("POST /channels/{channel_id}/contacts") is useful for developers but is the least essential element for an agent selecting a tool.

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 3-parameter, no-output-schema mutation tool the description covers the essentials (what, where, identifier semantics), and return values need not be explained. However, it omits any hint about behavior on duplicates or failure, which matters given the destructiveHint annotation.

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 already 100%, which sets the baseline at 3, but the description genuinely adds meaning beyond the schema by mapping identifier types to channel types (email channel → email address, WhatsApp/SMS/voice → phone number). The schema's own identifier text is vaguer about which channels map to which format.

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 ("Create a contact on a channel") plus the scope constraint that the contact belongs to a channel. This clearly distinguishes it from siblings like trengo_get_contact and trengo_update_contact, though it never names those alternatives explicitly.

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?

The description implies usage through context but gives no explicit when-to-use, when-not, or alternative (e.g., import vs. single-create, or updating an existing contact instead). An agent must infer from the verb alone that this is the single-record creation path.

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