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

With no annotations, the description carries the full burden. It usefully discloses cost ('Free') and that results are 'current', but says nothing about subscription expiry, polling/rate behavior, or what happens with an invalid or expired id.

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 short sentences with the cost notice front-loaded and the core behavior immediately after. No wasted words, though 'Free.' alone as a lead fragment is slightly abrupt.

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 one-parameter read tool with no output schema, this is close to sufficient: it covers what is returned, that it is current, that it is free, and where the id originates. The missing piece is defining what a 'match' contains and how an invalid id behaves.

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 0% and the single `id` parameter has no description, so the description must compensate. It does add the important provenance detail that the id comes from `subscribe`, but gives no format, length, or validity constraints beyond that.

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 concrete verb ('Returns') and a concrete resource ('current matches for a subscription id'), and names the sibling that produces the id ('subscribe'), which separates it from the creation tool. What a 'match' actually is remains undefined, so it stops short of a 5.

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?

The phrase 'created with subscribe' implies the prerequisite and implicitly routes the agent to the sibling that mints the id, but there is no explicit when-to-use/when-not guidance or mention of alternatives such as get_feed.

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