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

With no annotations, the description carries the full behavioral burden. It does disclose that it reads the public cache and does not trigger a full analysis (useful cost/freshness context), but says nothing about read-only guarantees, what happens when a ticker has no published VI Score, or whether the cache can be stale. For a tool with zero annotation coverage this is a substantial gap.

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 short sentences with zero filler; the comparison scope and the cache-read caveat are front-loaded, so an agent gets the essentials immediately.

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 one-parameter tool with full schema coverage, the description is nearly sufficient and partially compensates for the missing output schema by naming the returned fields (price, P/E, note /100). It falls just short on edge-case behavior (missing/unpublished scores) and the absent annotations.

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 single symbols parameter already documents the 2-8 ticker constraint with an example. The description adds no syntax or format detail beyond that, so the baseline 3 applies.

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 (compare) and resource (stocks) and goes further by naming the comparison basis — the published VI Score — plus the fields surfaced (price, P/E, note /100). It implicitly distinguishes itself from analyze_stock via 'without re-running a full analysis', though no sibling is named outright.

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 phrase 'Lit le cache public, sans relancer une analyse complète' implies the usage context — use this for lightweight comparison rather than a full analysis. However, it never explicitly states when to prefer this over analyze_stock or screen_stocks, leaving the agent to infer the routing.

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