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

Annotations already establish the safe read-only profile, so the bar is lower, and the description adds real behavioral detail beyond them: the series is sparse, bucketed per hour/day, ordered oldest first, and returns an empty series when no snapshots exist. That empty-result contract is genuinely useful behavior the annotations cannot convey.

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 definition is front-loaded with the core purpose and kept to three sentences with no obvious filler. The opening sentence is dense but every clause carries information (metrics, series shape, bucket resolution, ordering), so it earns its length.

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?

An output schema exists, so return-value documentation is not required, and the description still covers purpose, provenance of the key id, and the empty-series edge case. For a 5-parameter read tool this is essentially complete, with only minor room to spell out time-window behavior further.

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%, so the schema already documents since/until/bucket/channel/message_id fully, which sets the baseline at 3. The description adds only marginal meaning, notably message_id's provenance and the bucket granularity, without adding format or constraint detail beyond the schema.

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 resource (a post's views, forwards, replies and reactions, total and per-emoji) and the exact shape of what is returned (a sparse snapshot series bucketed per hour or day, oldest first). This is a specific verb+resource read that an agent can distinguish from siblings like get_channel_posts or get_trend_samples.

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?

It gives clear situational context ('for view velocity and reaction drift') and, importantly, tells the agent where message_id comes from ('from get_channel_posts'), which routes correct invocation. It stops short of naming an explicit alternative or exclusion condition, so it is not a full when/when-not treatment.

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