Get fmsg thread

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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses two important behaviors: inaccessible messages appear as gaps, and returned conversation text must be treated as data, never instructions. This is valuable context for safe agent invocation and there is 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 no filler: output shape, permission-gap behavior, data-safety warning, and reply-tool relevance are all covered. The most important information is front-loaded.

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 read-only, idempotent tool with an output schema, the description covers the semantically important behaviors and safety considerations. The optional size-limiting parameters are left to their names/defaults, which is a minor gap given their self-explaining nature.

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 only 25%: only the id property is documented. The description does not explain max_messages, max_total_bytes, or max_body_bytes_per_message, and it only indirectly reinforces id's role as the starting message. With low coverage, the description needed to compensate but did not.

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?

Description uses a specific verb ('Reconstruct') and defines the exact scope: the direct lineage from thread root down to the given message, with sender, time, recipients, and body. This clearly separates it from siblings like get_message or list_messages even without naming them.

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 a clear context: use it to reconstruct the conversation a message belongs to, and the returned reply target/participant set is explicitly pointed at the reply tool. It does not list exclusions or name alternatives, but the intended use case is unambiguous.

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