Altcoin Season Index (live + recorded history)

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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), and the description adds real substance beyond them: the exact computation window, venue universe, and the >=75 / <=25 thresholds that define altseason vs bitcoin season. The provenance note "recorded daily history (never reconstructed)" is a valuable data-integrity disclosure an agent could not infer from structured fields.

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 dense sentences with zero filler: the trigger condition leads, the returned content and its semantics follow. Every clause carries information (thresholds, universe, provenance).

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 no output schema, the description carries the return-value burden and does so: live index value plus interpretation bands, strongest/weakest large alts, and recorded daily history. Nothing an agent needs to select or call the tool is missing.

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 the baseline is 4. The description correctly adds nothing parameter-related, since there is nothing to disambiguate.

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+resource: returns the live Altcoin Season Index along with strongest/weakest large alts and daily history. The index definition (share of top 50 Binance perp alts beating BTC over 90 days) makes it unmistakably distinct from siblings like get_market_indices, get_theme_indices, and get_factor_board.

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?

"Call this when the user asks whether it is altseason, how altcoins are doing against Bitcoin, or about market rotation" gives explicit triggering conditions tied to user intent. It does not name an alternative tool or a when-not-to-use case, so it stops short of a 5.

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