list_source_sets

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

With no annotations, the description carries the burden, and it does disclose important behavior: it lists both complete and incomplete sets, names missing filenames for incomplete ones, and warns that a close over an incomplete period would be refused. It clearly explains that the useful answer for a short month is a list showing the missing file, not an empty list. Some behavioral details (e.g., whether this mutates anything, exact output format) are missing, but the disclosure is informative.

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?

The description is compact and front-loads the core purpose in the first sentence, then expands on the important edge-case behavior. It is not bloated. The phrasing is a bit oblique ('Which periods'...' as a fragment) but overall it earns its sentences.

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?

The description gives a good sense of output semantics (complete/incomplete, missing filenames, refusal of close over incomplete data), and there is an output schema present, which may carry return-value details. However, with no annotations, no parameter semantics, and no explicit statement about whether this is a read-only inspection tool (likely, but unstated), an agent has a moderate gap. For a one-parameter list tool with an output schema, this is just adequate.

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 0% and the description never mentions the 'loop' parameter. The only parameter is required, but an agent is given no semantic clue what a 'loop' is in this domain. The description would need to at least tie 'loop' to a period identifier or scope to make the tool callable with confidence.

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 the resource (source sets for periods) and the key behavior (listing which periods' source files are on disk, complete or not), but it uses the informal phrase "Which periods' source files are on disk" rather than a direct verb like 'List'. The sibling set includes list_runs and list_loops, so the period/source-set scope does help distinguish it. However, the intended operation is somewhat implied rather than crisply stated as 'List the source sets for each period'.

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 second part explains a subtle usage context: incomplete periods are listed with missing filenames, and a close over a half-arrived period is refused, so the tool's output provides the diagnostic answer rather than an empty list. This implicitly tells the agent when to use it (when investigating whether periods' source data is complete, e.g., before closing) and what to expect. It does not explicitly name alternatives or say 'use X instead', but the context is reasonably clear.

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