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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered by structured data. The description adds two genuinely useful behavioral facts beyond that: the data is public Polymarket data, and probabilities are reported by the source rather than computed internally. It still says nothing about what is returned, whether the set of markets is fixed or live, or whether the call can be slow or fail when the upstream source is unavailable.

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?

A single compact sentence with no filler, front-loading the resource being inspected before the provenance caveat. It could be tightened slightly (the phrase "observations, probabilities are source-reported only" is a clause splice), but nothing is wasted.

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?

With no parameters and no output schema, the description carries more of the burden than usual, and it only partly meets it: it names the subject (event markets and their probabilities) but never indicates what a result looks like, how many markets come back, or whether the data is a live snapshot versus a cached observation. The overlap with the sibling "market_snapshot" is also unaddressed, so an agent cannot confidently confirm this is the right call.

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 zero parameters and the schema is an empty object, so there is no parameter meaning for the description to convey. Baseline credit applies; the description correctly implies a parameterless inspection call without inventing filtering options that the schema does not support.

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 pairs a specific verb ("Inspect") with a specific resource ("public Polymarket event-market observations"), so the agent knows this is a read of prediction-market data rather than a task-management or token tool. It does not, however, distinguish itself from the sibling "market_snapshot", which plausibly overlaps in subject matter, leaving the agent to guess which of the two is appropriate.

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?

There is no explicit statement of when to use this tool, when not to, or which sibling to choose instead. The qualifiers "public" and "event-market" narrow the domain implicitly, and "probabilities are source-reported only" is a data-provenance caveat rather than usage routing, so the agent gets almost no selection guidance.

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