Read messages from a WhatsApp chat

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

Annotations already mark the tool as read-only and idempotent; the description adds valuable behavior beyond that: default ordering, backwards pagination semantics, and the fact that wazap may query the phone for older history with a noticeable delay. This contextualizes side-channel behavior and latency without contradicting 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?

The description is compact, front-loaded with the core operation, and every sentence provides distinct value: ordering, default behavior, and pagination delays. No filler or reduntant restatement.

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?

The description covers the key non-obvious behavior (pagination, phone lookup, delay) and does well given the annotations and full schema. The only gap is that it does not describe the returned messages shape since there is no output schema, but an agent can largely infer it from the tool's purpose.

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 100%, so the baseline is 3. The description goes beyond the schema by explaining how `before` is meant to be used (the oldest message_id already held) and that reading will fetch newer history from the phone when the local store runs out. This adjusts to 4.

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?

The description names a specific action ('Read messages') and resource ('from one chat'), and states ordering as 'oldest to newest.' It also explains the default behavior with and without `before`, which distinguishes this from single-message or search-based sibling tools.

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 gives an explicit usage condition: omit `before` for the most recent messages, or pass the oldest message_id you already have to page further back. It also warns about a phone-side delay. It does not name alternatives like get_recent_messages or search_messages, so implicit rather than explicit tool-selection guidance.

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