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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds important behavioral context: it reads live from Instagram, is slower than most tools, covers one account at a time, and returns only short excerpts. It also explains the meaning of the handedOverByFlow, flowNotice, and cameFrom flags, which is valuable for interpreting rows.

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 purpose is front-loaded and every sentence mostly earns its place by explaining return fields, flags, and limitations. However, the description is long and uses dense semicolon-linked clauses rather than a more scannable structure, so it is informative but not maximally concise.

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?

Given no output schema and only two simple annotations, the description provides a thorough account of what rows represent, what the key flags mean, what is not included, and which sibling to call for full messages. It also covers the live-read performance trade-off and single-account scope, making it complete for correct invocation.

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 limit and instagramAccountId parameters are fully documented in the schema itself. The description mentions one account at a time and most recently active first, but does not add parameter-level syntax or constraints beyond what the schema already provides; baseline 3 is appropriate.

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 states a specific verb (read/list) and resource (Instagram direct message conversations on a connected account), with ordering and key fields. It clearly distinguishes itself from inbox_thread for actual messages and from referrals_overview for the affiliate programme, so an agent can identify the right tool without opening schemas.

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?

It gives explicit use cases such as 'what is in my inbox', 'who has written to me', 'is anyone waiting for a reply', and 'which of my ads are people messaging me from', plus finding thread and person ids for other inbox tools. It also names the alternative inbox_thread for actual message content and clarifies the relationship to referrals_overview, leaving little to inference.

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