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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the shape of the returned explanation, which the output schema already carries, and says nothing about rate limits, lookup failure behavior for unknown keys, or freshness of 'current value'.

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 that lists the three outputs in priority order with no filler. It is a sentence fragment rather than a complete statement, which costs it the top mark, but nothing needs trimming.

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?

The tool is simple: one required enum parameter, full schema coverage, and an output schema that carries return-value detail, so the description need not explain the response. The description covers the core purpose adequately; only explicit sibling routing and failure behavior for an invalid indicator key are 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?

There is a single parameter with 100% schema description coverage and a 10-value enum, so the schema already tells the agent exactly what to pass. The description adds no meaning about the 'name' key beyond what the enum and its 'Indicator key' description provide; baseline 3 applies when the schema does the heavy lifting.

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 specific verb (explain) and resource (one Barometer indicator) and enumerates the three things it returns: what the indicator measures, its current value/heat, and its contribution to the score. That is enough to distinguish it from get_history and get_market_snapshot, though it never explicitly names those siblings.

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?

Usage is implied by the phrasing 'how it feeds the score' — an agent would call this when it needs to understand a single indicator or justify a score contribution. However, there is no explicit when-to-use, no when-not-to-use, and no mention of the sibling tools that might otherwise be reached for.

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

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

Annotations already declare the safe, idempotent, closed-world read profile, so the bar is lower. The description still adds real context annotations do not carry: the data source (public daily history), the default range behavior, and the 'auto picks the finest that fits 400 points' constraint — a meaningful disclosure about result granularity.

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?

Compact and front-loaded, with the resource named first and the parameter behaviors ordered by importance. The opening 'Heat Score history from the public daily history' is slightly awkward and could be tightened, but there is no wasted sentence.

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 values need not be explained, and the description still notes that 'a summary covers the whole range'. For a 3-parameter read tool this is nearly sufficient; the only gap is the absence of guidance on when this history differs from the sibling indicator/market tools.

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 already 100%, so baseline is 3, but the description genuinely extends the schema: it explains 'from'/YYYY-MM-DD requirement, the 'to' default, and what 'auto' actually does (finest interval fitting 400 points), which the enum description 'Point size (default auto)' does not convey.

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 clear resource (Heat Score history) and verb (retrieve from the public daily history), which is specific enough to act on. It does not, however, distinguish itself from the siblings explain_indicator or get_market_snapshot, so the agent must infer the boundary.

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?

Usage conditions are implied rather than stated: the required 'from' and the 'to' default communicate the expected range pattern, but there is no explicit when-to-use-this-vs-a-sibling guidance or prerequisite/exclusion language.

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

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered structurally. The description adds one useful behavioral note — 'Descriptive only,' implying no advice or interpretation is returned — but says nothing beyond that about freshness, caching, or limits.

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 sentences, front-loaded with what the snapshot is before listing contents. The content enumeration overlaps with the output schema, but the brevity keeps it from being wasteful.

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?

A parameterless read-only tool with full annotation coverage and an output schema needs little description; this one tells the agent what domain data it returns and that it is descriptive only. The only real gap is that it does not help route between the three sibling tools.

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 there is nothing for the description to disambiguate. Baseline 4 applies; no parameter-level confusion is possible.

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 names a specific resource (the Bitcoin Barometer reading) and enumerates exactly what the snapshot contains — Heat Score, zone/bands, comparative periods, BTC price changes, and the ten indicators. It is clear what the tool returns, but it never distinguishes itself from siblings like get_history or explain_indicator, which an agent could plausibly confuse given the mention of 'yesterday and last week'.

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?

'Descriptive only' hints at the tool's role as a data-only read, but the description gives no explicit when-to-use guidance and never names an alternative. An agent choosing between this, get_history, and explain_indicator gets no routing signal.

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