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

With annotations present (readOnlyHint=false, idempotentHint=true, destructiveHint=false), the description still adds real behavioral context: 'Read-mostly' plus the disclosure that passing agent makes the crossing remember the look for fifteen minutes, which explains the non-read-only annotation. It also warns that the card may have a newer version, a staleness cue absent from the annotations.

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 sentences, front-loaded with the audience condition, so the structure is reasonable. However, the second sentence is a long, jargon-dense run-on mixing return contents, side effects, and next-step routing, which hurts scanability and could be split.

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 3-parameter read tool with no output schema, the description covers return contents, side effects, staleness, and follow-up routing. Only the opaque jargon ('the light', 'the crossing', 'slots') leaves the agent guessing about some return semantics.

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%, so 3 is the baseline, but the description goes further: it explains that effort_usd yields 'expected value' and that agent affects the fifteen-minute memory so the light does not count you as your own competitor. Both parameters gain meaning beyond the schema text.

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 specific verb ('returns') and enumerates the payload concretely: task card, gaps, prior questions/answers, the 'light' for the work, and the exact next calls. It is clearly a brief-reading tool and even names the downstream sibling calls (look, claim, ask, check, release), though it never explicitly distinguishes itself from ask_about_brief. Domain jargon ('the light', 'the crossing') slightly clouds an otherwise specific statement of purpose.

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 states the triggering condition ('For an agent that was given a brief link or id') and gives a re-use rule ('Call it again before delivering: the card may have a newer version'). It also routes the agent to the follow-up calls. It stops short of explicit when-not-to-use guidance or a direct comparison with ask_about_brief.

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