List archived spans

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

Adds context beyond annotations: local files, no network access, newest-first ordering, and the two distinct return formats ('<run>: <n> spans' per run vs. a line per span given run). Annotations already cover the read-only/idempotent/non-destructive profile, so this is solid added value; only minor gaps like pagination/truncation behavior remain.

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?

Three tight sentences that front-load the purpose, then siblings, then environment and output shape. No filler; every clause carries routing or format information.

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 two-parameter read-only list tool with no output schema, the description supplies the essential output shape and environment context. It could mention what a span record contains or whether results are truncated at 'max', but coverage is otherwise strong.

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 baseline is 3, but the description adds meaning the schema lacks: omitting 'run' yields per-run summary counts, while supplying it yields per-span lines. That is real semantic value beyond the field descriptions.

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?

States a specific verb and resource ('Browse the span archive') plus a distinguishing scope condition ('no search term'), and explicitly names the sibling tools for other purposes. An agent can tell it apart from search_spans and read_span immediately.

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?

Gives explicit routing: use search_spans for known text, read_span to open one, and this tool for browsing without a search term. Also clarifies the run parameter changes the output shape, so when/when-not is fully covered.

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