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

With no annotations, the description must carry behavioral disclosure. It reveals that the checkpoint only moves forward and is shared across sessions, which is important. However, it does not mention return values, error behavior, idempotency, or consequences of invalid input. This is partial transparency.

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 short but structurally flawed: 'Pass the nextAfter the read returned' is a broken sentence. While the first sentence is front-loaded and clear, the second undermines readability. This is under-specification combined with poor wording, not tight conciseness.

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 mutation tool with no annotations and no output schema, the description leaves key gaps. It fails to explain the 'through' parameter clearly, does not specify what the tool returns (if anything), and omits what happens on invalid input. Despite the simple surface, the ambiguities make it insufficient 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 0%, so the description must compensate. It references 'nextAfter' as something to pass, likely mapping to 'through', and 'your account' for 'account'. But the sentence is malformed ('nextAfter the read returned') and does not clearly define either parameter. It provides some meaning but is confusing and incomplete.

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 action ('Move your inbox checkpoint') and the trigger condition ('after you have handled a page'). It distinguishes from siblings like list_inbox by indicating it advances the cursor rather than reading. The garbled second sentence slightly reduces clarity, but the core purpose is evident.

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 implied usage context: call after handling a page and pass the cursor token from the read. It does not explicitly name alternatives or state when not to use it. The forward-only movement hints at a sequencing constraint, but there is no clear exclusion or comparison with other tools.

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