replay

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

With no annotations, the description carries the full burden and only discloses the merge and ordering behavior. It says nothing about whether this is a read-only disk scan or a network call, how 'limit' interacts with the merge (per-channel vs global truncation), how ties across channels at identical timestamps are ordered, or whether duplicate records are deduplicated.

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?

A single front-loaded sentence with no filler, which is structurally sound. However, for a six-parameter tool with required time bounds, that brevity tips into under-specification rather than economy.

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?

Six parameters, four required, no annotations, no output schema, and 17% schema coverage mean the description should explain units, filtering semantics, and result shape. It supplies none of that, so an agent could not confidently construct a call from this definition alone.

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 only 17%, so the description must compensate, yet it only alludes to 'channels'. It never explains that start_ns/end_ns are nanosecond bounds, what symbols filter relative to channels, or what limit caps. The one documented field (asset_class, inferred from symbol source) is documented in the schema, not the description.

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 concrete verb ('merge'), a resource ('stored channels'), and the shape of the result ('one globally time-ordered record stream'), which tells an agent this is a multi-channel temporal merge rather than a plain fetch. It does not differentiate from plausible siblings like query, query_market_data, or resample, which likely also return time-ordered market data.

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?

No guidance on when to use this instead of query, query_market_data, resample, or export, all of which operate on similar stored data. There is also no mention of prerequisites such as channel names needing to come from catalog-channels or list_data_channels.

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