stats

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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, and the description adds meaningful context beyond them: no model call is made, results are never cached, and council/chain records carry quorum/consensus/synth_fallback. It still doesn't say whether results are paginated or how stale the aggregation is, so it isn't exhaustive.

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-loads purpose, then window/by, then filters, then reporting fields, then examples. Every sentence carries information (what is aggregated, how it can be sliced, what is returned, what constraints apply) with no filler.

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?

There is no output schema, and the description compensates by enumerating the returned metrics (calls/allowed/refused/errors, avg and p95 latency, error_rate, totals). Combined with the filter and window semantics, an agent has everything needed to call and interpret this tool.

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 100% and the by enum's own description already explains provider vs model attribution, so the schema does the heavy lifting. The prose restates only three of the eight bucket keys ('model', 'session', 'day'), adding little syntax or semantics beyond the schema's own 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?

States a specific verb and resource: read-only usage/health stats aggregated from the ask_fable audit log, with named bucket dimensions (by) and time windows. The scope ('without spelunking JSONL') clearly separates it from the ask_* generation tools and trace/log inspectors.

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 concrete motivating questions ('is GLM erroring a lot today?', 'how slow are councils this week?') that make the intended use obvious. It does not, however, explicitly name an alternative or say when not to use it (e.g., vs session_stats), so it stops short of full routing guidance.

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