configure_tracing

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

Far exceeds the annotations (which only say not-read-only, idempotent, non-destructive). The description discloses the exact side effect (config file write), the precedence relationship with env vars, the timing ('applies on the next call'), and the distinct consequences of each mode including redaction and markdown saving.

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 with the core action and effect, and the operational details (config precedence, no restart) follow logically. It is dense with long parentheticals and duplicates much of the schema's parameter text, which costs it a point.

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?

Even without an output schema, the description states the return value ('the effective settings and the config path') and covers persistence, timing, and scope of effect. An agent has everything needed to invoke it correctly.

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% and the enum is documented there, so the baseline is 3. The description adds the combinatorial rule 'Pass either or both' and reiterates the override behavior, which is meaningful beyond the schema but largely redundant with the per-parameter 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 ('Toggle reasoning-trace capture at runtime') plus the persistence scope ('persisted across sessions'). It is clearly distinguishable from sibling read tools like trace_list and trace_get, since this one mutates configuration rather than reading traces.

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 strong operational context: it writes the ask_fable config file, overrides the ASK_FABLE_TRACE_MODE / ASK_FABLE_STREAM_REASONING env defaults, requires no ~/.claude.json edit or restart, and applies on the next call. It does not name a competing tool to use instead, but no sibling offers this capability, so the missing exclusion is minor.

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