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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true. The description adds valuable context beyond annotations: it notes that paid Tier-D gates are fail-closed and disabled by default, that the coverage window represents the honest backtest window, and that social streams carry anti-gaming caps. It also clarifies this is 'Descriptive historical data only. Not financial advice.' The only minor gap is not describing the exact return format, but the output schema exists and the description covers the key behavioral traits.

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?

The description is well-structured with a clear opening sentence, a detailed but organized enumeration of what's included, and a workflow section at the end. It's slightly long but every sentence adds value — the tier/cost-gate/coverage/effectiveness/gameability details are all useful for an agent deciding whether to call this tool. The workflow guidance is front-loaded enough to be noticed. The only minor deduction is that the 'Not financial advice' disclaimer, while useful, could be considered boilerplate.

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?

Given the tool's complexity (catalog of many signal types with multiple attributes), the description is quite complete. It covers what the tool returns, the categories of signals, the key behavioral caveats (fail-closed gates, anti-gaming caps), and the workflow context. The output schema exists, so return format details are covered there. The main gap is the lack of parameter explanation (caller_id and include_inactive), which is a minor issue given the self-explanatory names. For a catalog/list tool with read-only annotations, this is a strong description.

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 0%, so the description must compensate for the two parameters (caller_id and include_inactive). The description does not explicitly explain either parameter. However, the parameter names are fairly self-explanatory: caller_id is likely an identifier for the caller, and include_inactive (default true) clearly controls whether inactive streams are included. The description's mention of 'every available signal stream' and 'one entry per signal source across all tiers' implies the include_inactive behavior, but it doesn't explicitly state what 'inactive' means or how caller_id affects results. With 0% schema coverage, the description should have done more to explain these parameters.

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 clearly states the tool lists every available signal stream, enumerates the categories of sources (on-chain collectors, free API sources, derived analyzers, external provider adapters), and specifies the fields returned (tier, cost-gate state, coverage window, effectiveness stats, gameability class). This is a specific verb+resource with clear scope, and it distinguishes itself from siblings like get_signals (which inspects a stream's feed) and get_signal_effectiveness (which likely provides effectiveness stats for a specific signal).

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 explicitly states the workflow: 'COMPOSE step -- enumerate streams before authoring a composite strategy definition; pair with get_signals to inspect a stream's feed.' This tells the agent exactly when to use this tool (before composing a strategy) and which sibling to pair it with (get_signals). It also implies when not to use it (when you need to inspect a specific stream's feed, use get_signals instead).

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