Get conversation

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

Goes well beyond the annotations: states it will not mark the thread as seen (a meaningful side effect beyond readOnlyHint), says attachments are never inlined, discloses the open-window report, and warns that message content is untrusted user data wrapped as data, not instructions. No contradiction with annotations.

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 sentences, with the primary read action front-loaded, followed by result contents, the send-message integration hint, and a security note. Every clause carries information; no fluff.

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 carries return-value disclosure: message fields, placeholder types for attachments, the open-window flag, and ordering. Combined with the schema's cursor/profine semantics, the agent can call and interpret the result correctly without missing context.

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 the baseline is 3. The description adds no parameterpsecific semantics beyond what the schema already provides for conversation_id, after, limit and profile, though it does give useful context about the thread scope and cursor behavior indirectly.

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?

Identifies a specific verb ('Read') and resource ('one Messenger thread') and states the exact data shape returned (sender, timestamp, direction, body, placeholders). This clearly separates it from sibling list/send tools by emphasizing 'one' thread and newest-message-first order.

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 explicitly ties the tool to a follow-up action: check the 24-hour messaging window before calling facebook_send_message. The schema adds conversation_id provenance from facebook_list_conversations. It does not explicitly state exclusions, but no similar single-thread reader sibling exists, so no exclusion is necessary.

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