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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that: it names the upstream source (StockMap's Altseason page), discloses the comparison baseline (a typical week), and requires surfacing the stamp, sources and not-advice line — a disclosure obligation an agent would otherwise miss.

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 short sentences, front-loaded with the metric definition before the source and the output obligation. The first sentence is dense and slightly awkward ('beside how many lag it in a typical week'), but no sentence is redundant.

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?

With an output schema present, return-value explanation is unnecessary, and the description covers the metric definition, data provenance, and a presentation requirement. For a no-argument single-metric tool this is essentially complete, with only sibling routing left unaddressed.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a 0-param schema applies. No misleading parameter-like language is introduced.

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?

The description states a precise metric: the count of top-100 non-stablecoin coins that beat Bitcoin over 7 days, compared against how many lag in a typical week, sourced from StockMap's Altseason page. That is far more specific than the title alone. It does not explicitly distinguish itself from siblings like crypto_today or bitcoin_test, so it stops short of a 5.

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?

Usage context is only implied: the reader infers this is the tool for answering the 'altseason' question and for market breadth data rather than price lookups. There is no statement of when to prefer it over crypto_today, market_map, or bitcoin_test, and no exclusions.

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