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

readOnlyHint=true already tells the agent this is a safe read; the description reinforces that it returns the latest batch but says nothing about volume, ordering beyond "latest", or whether items can be marked read here. No contradiction with annotations, but the added behavioral context is thin.

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?

Two tight sentences: the first defines the resource and its source, the second gives the priority cue plus the redundancy note. Nothing is wasted and the guidance 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 zero-required-parameter read tool with annotations covering safety and a fully described schema, this is nearly complete. Only the shape of the returned announcements (and how to act on them, e.g. reply_to_sun) is left implicit.

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 single optional token parameter is already documented as pulling the unread inbox count, so the description adds no parameter detail. Baseline 3 applies when the schema carries the full burden.

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 resource (in-app announcements) with a named source (Sun, the CityDesk operator), which distinguishes it from every sibling in the list. An agent can tell exactly what it retrieves 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?

"Read these first" gives an explicit ordering cue relative to the rest of the workflow, and it names list_tasks, list_listings and get_contest as tools that also surface the latest announcement, so the agent knows it can skip this call in those flows. It stops short of saying when this tool is the wrong choice or when to re-poll.

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