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

Adds substantial context beyond the annotations: explicit credit spend (~$0.06 engine cost plus plan margin), the budgetUsd cap and its default/max, and the chargedUsd reporting of actual cost, plus the write-scope requirement — all reconciling with readOnlyHint=false. The destructiveHint=true is left unexplained (nothing here indicates what, if anything, is mutated or lost), which is the one behavioral gap.

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?

Front-loads the operation and flags the cost warning early with 'SPENDS CREDIT:', and every clause carries information. It is dense to the point of being hard to parse in the first sentence ('How much X is talking about 2 to 6 short phrases right now: …'), and 'billed with the plan's margin' is marginal detail, but nothing is padding.

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 and 100% parameter coverage, the description only needs to cover invocation context — and it covers cost, budget and auth scope well. The remaining critical gap is tool selection: an agent choosing between current_pulse and x_pulse gets no signal here, and the '2 to 6' phrase count conflicts with the schema.

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 coverage is 100%, so baseline is 3; the description restates budgetUsd's default/max (matching the schema, so little added value) and mentions the non-parameter chargedUsd output. It also claims '2 to 6 short phrases', which conflicts with the schema's minItems: 1 — a mismatch that could mislead rather than clarify.

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?

Names a specific verb/resource combination ('measure how much X is talking about phrases right now') and enumerates the concrete outputs (7-day volume, per-day counts, velocity, sample posts, wave flag), so the agent knows exactly what it produces. However, it never distinguishes itself from the near-identical sibling x_pulse (nor community_hot/related_trends), which is exactly the differentiation a 5 requires.

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?

Prerequisites are stated ('Needs the write scope') and operational bounds are given (budgetUsd default 2, max 10), which tells the agent how to call it safely. But there is no 'use this when…' / 'use x_pulse instead when…' routing or any exclusion, so the choice between this and the sibling x_pulse is left entirely to inference.

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