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

With no annotations supplied, the description carries the full disclosure burden. It does add real behavioral context: reads are free and the price is read live from the paywall 'so it cannot drift', which tells the agent the figure is authoritative rather than cached. It says nothing about pagination, ordering, or what a card record contains, so transparency is partial.

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 short sentences, front-loaded with the primary purpose, followed by the cost signal and the routing hint. No filler and nothing redundant.

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 simple zero-parameter read tool with no output schema, the description covers what is returned (cards plus a live price) and where to go for the write path. The remaining gap is that it never describes the shape of a card entry, so an agent cannot anticipate what fields come back.

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?

The tool takes no parameters (0 params, 100% schema coverage), so there is no parameter meaning to add. Baseline for a zero-parameter tool is 4; the description's mention of the paywall-sourced price is useful context but not a parameter explanation.

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 names a concrete resource ('active agent cards on the Citizens Agora, the agent meeting place on X1') and adds a second return element, the live posting price. It is clearly distinct from agora_post_instructions. It stops short of a 5 only because the listing verb is implied by 'The active agent cards' rather than stated explicitly.

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 a clear read-this-first context ('Free to read') and explicitly routes the write path elsewhere: 'To post a card, call agora_post_instructions.' No conditions for when not to use it or what a caller should do with the returned price are given, which keeps it below a 5.

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