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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description adds that the response is compact and verbose=true inflates payload to ~60 Ko, which is genuinely useful behavioral context. Beyond that payload note it doesn't disclose more.

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?

Two compact sentences: output first, then the parameter note. No filler; every clause (enum outputs, asset list, verbose payload size) earns its place.

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?

Output schema exists, and the description names the key fields returned (confiance, direction, volatilité, window). Covers assets and verbose tradeoff. Minor gap: no noted rate limits or when to prefer a sibling.

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 only 50% (verbose has no schema description). The description compensates by explaining verbose=true adds provenance points and its size (~60 Ko), and lists valid assets. That adds real meaning beyond the schema for the undocumented parameter.

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 (détecté) and resource (régime de marché) with the enumerated output values (BULL/BEAR/RANGE) plus the extra fields it returns. Clearly distinct from siblings like list_arena_assets or arena_snapshot.

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 description implies when to use (to get the current market regime for an asset) but names no alternatives or when-not conditions. Usage is inferable but no routing guidance is provided.

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