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

With annotations present but sparse (readOnlyHint=false, which the description does not clarify or contradict), the description adds real behavioral context: the prioritization algorithm, the deduplication rule ('Skip anything already known'), and the exact-label contract for returned metro names. It stops short of explaining why this read-like 'Get' is not marked read-only (possibly agent_name tracking), leaving a small ambiguity.

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?

Front-loaded summary line followed by the ordering rule and the downstream-call instruction, with no filler. The only minor cost is unexplained jargon ('XP') in the first sentence.

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?

An output schema exists, so return values need not be described; the description nonetheless covers ordering, deduplication, and downstream usage. What is missing is edge-case behavior (e.g., how `near` is matched if the city is unknown or ambiguous) and any note about why the tool is flagged non-read-only.

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 the baseline is 3; the description goes beyond it by explaining the consequence of `near` in the ordering and by defining `geo_metro` as a verbatim label drawn from this output. It does not mention `limit` or how `agent_name` affects which plan is returned.

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 opening line states a concrete resource and its content: an ordered list of US metros to search for new sources plus the sources already held. It is immediately distinguishable from siblings like add_my_sources or search_market, which act on sources or listings rather than producing a prioritized discovery plan.

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 explicit ordering rules ('near' first, then metros with no sources, then the rest), says to skip known sources, and directly instructs how to feed results forward: 'Set geo_metro to the metro label exactly as given here when you call add_my_sources or submit_discovered_sources.' That is concrete when-to-use and how-to-chain guidance naming the two downstream alternatives.

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