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

Annotations already declare idempotentHint=true and destructiveHint=false, which the description reinforces by stating repeated marking is idempotent. Crucially it adds behavior not in the annotations: partial-failure semantics (offending ids land in failed[] without failing the whole batch) and a login requirement.

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?

Front-loads the login requirement and organizes the rest into labeled sections (combo chain, pitfalls) with no filler sentences. Slightly dense with colloquial parentheticals, but each clause earns its place.

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 single-parameter mutation with no output schema, the description covers authentication, batch behavior, idempotency and partial failure, leaving no ambiguity an agent needs resolved before invoking it.

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% and the schema already documents deliveryIds as the inbox item id with a max of 100. The description repeats the source (items[].id) rather than adding syntax or format meaning, so the baseline of 3 applies.

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?

States a specific verb+resource (mark organization notifications as read) with clear batch scope, distinguishing it from siblings like mark_conversation_read and from the list_my_organization_notifications reader. An agent can identify the operation without opening the schema.

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?

Names the exact upstream tool that supplies the ids (list_my_organization_notifications, items[].id) and the workflow order (read a round, then clear). This is explicit routing guidance rather than implied usage.

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