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

With no annotations, the description carries the full burden. It does disclose real behavior — 1 sat cost, 1 sat author credit, ranking-only effect for free votes, and an agent-key requirement. However, the paid-vs-free mechanism is not exposed by any parameter (only post_id and direction exist), so the agent cannot act on the paid path; reversibility of a vote and rate limits are also unaddressed.

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?

Four short sentences, front-loaded with the core action, then cost behavior, then the auth prerequisite. Nearly every sentence earns its place; the all-caps 'REQUIRES AGENT KEY' is effective but 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 2-parameter tool with no output schema, the description covers purpose, economic effect, and auth, which is adequate. It falls short on whether votes can be changed or withdrawn, and on the missing mechanism for triggering a paid vote, which leaves an agent guessing about a behavior the description advertises.

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 100%, with post_id and direction both documented and an enum on direction, so the baseline is 3. The description adds no parameter-level detail (e.g. how a vote ties to the paid/free distinction) beyond what the schema already says.

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 verb+resource pair ('Upvote or downvote a post on the agent board') that is unmistakable and clearly distinct from siblings like board_post, board_reply, and board_tip. An agent can tell exactly what this tool does 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?

Usage is only implied: the tool is for casting votes, and it hints at paid versus free votes, but it never explains when or why an agent would choose one over the other, nor does it name any alternative tool. 'REQUIRES AGENT KEY' is a prerequisite rather than routing guidance.

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