GreenCalculus
GreenCalculus is a remote MCP server (with a thin local stdio/Docker bridge) that turns sourced greenhouse-gas emission factors into audit-traced carbon calculations.
Find factors:
search_factors(by section, key prefix, or free text) andresolve_factor, which maps plain-language descriptions — country included — to ranked candidates labelledacceptorreview.Fetch factors with provenance:
lookup_factorreturns the value plus an audit envelope — publisher, exact source cell, retrieval date, licence and redistribution terms, GWP set, and whether per-gas components sum to the headline. Unknown keys return candidate keys instead of a dead end. (lookup_factorsfor bulk fetches appears in the README table but not in the schema.)Calculate emissions:
calculate_activity(activity × factor, with unit conversion and GHG Protocol scope),calculate_electricity(Scope 2 location- and market-based),calculate_freight(GLEC tonne-km, Cat 4 & 9),calculate_business_travel(Cat 6, with/without radiative forcing),calculate_spend(EEIO screening),calculate_embodied(EN 15978 whole-life carbon, missing stages flagged not-assessed), andcalculate_pcaf(financed emissions with attribution factors and data-quality scores).Explain gaps:
explain_absenceclassifies why a factor is missing —structural,not_yet_sourced,refused,held_not_counted, orcoupled— naming the publisher, route, confidence, and review date.Work without a key for discovery (
initialize,tools/list),search_factors, andexplain_absence; all other tools need a free API key.
GreenCalculus MCP server
Sourced greenhouse-gas emission factors and audit-traced carbon calculations, as an MCP server. Every value comes back with its exact source cell and a pinned data version — so an agent hands back a number a person can cite and a machine can reproduce, instead of a guess.
Do you need this package?
Probably not. The server is remote, and if your client speaks remote MCP you should point it straight at the URL — nothing to install, nothing to update:
{
"mcpServers": {
"greencalculus": {
"url": "https://mcp.greencalculus.com",
"headers": { "Authorization": "Bearer YOUR_KEY" }
}
}
}This package exists for the clients that can only spawn a local stdio process, and for docker run installs. It is a thin bridge: it forwards each JSON-RPC message to the remote server and returns the reply verbatim. No method is special-cased, so new tools appear here without a release.
Related MCP server: AI Impact MCP
Use it over stdio
{
"mcpServers": {
"greencalculus": {
"command": "npx",
"args": ["-y", "greencalculus-mcp"],
"env": { "GREENCALCULUS_API_KEY": "YOUR_KEY" }
}
}
}Or with Docker — -i is required and -t must be omitted, because the container's stdin/stdout are the transport and a TTY corrupts the stream:
{
"mcpServers": {
"greencalculus": {
"command": "docker",
"args": ["run", "-i", "--rm", "-e", "GREENCALCULUS_API_KEY", "greencalculus/mcp"],
"env": { "GREENCALCULUS_API_KEY": "YOUR_KEY" }
}
}
}Get a free key at https://greencalculus.com/developers — no card. Discovery (initialize, tools/list) works without one, and so do search_factors and explain_absence; every other tool needs a key.
Tools
Tool | What it does |
| Fetch one emission factor by key, with its source and version |
| Fetch many factors by key in one call — a portfolio is one request, not one per factor |
| Search the corpus by free text |
| Map a messy real-world description to the best-matching factor |
| Say why a factor does not exist, rather than returning nothing |
| Activity → emissions, with unit conversion and GHG Protocol scope |
| Location-based and market-based electricity |
| Embodied carbon (EN 15978), explicit about missing lifecycle stages |
| PCAF financed emissions, with the audit trail |
| Freight by mode, distance and load |
| Spend-based EEIO |
| Business travel across modes |
Configuration
Variable | Default | Meaning |
| — | Your API key. |
|
| Override the endpoint. |
|
| Per-request timeout. |
Diagnostics go to stderr. Nothing but JSON-RPC is ever written to stdout — a stray byte there corrupts the session.
Develop
npm test # unit tests, no network
node bin/greencalculus-mcp.js # reads JSON-RPC on stdin
docker build -t greencalculus/mcp .Releasing
Bump version in package.json, merge to main. That's the whole procedure.
release.yml asks npm and the MCP registry
whether they already have that version and publishes only where they don't, so
a merge that bumps ships it and a merge that doesn't is a no-op. It also runs
weekly, so a publish that failed is retried without a new commit.
server.json is the registry manifest, and the workflow rewrites its version
from package.json before publishing — one source of truth, three places that
have to agree.
npm authenticates by trusted publishing,
so there is no npm token here. The registry needs one secret, and the reason is
worth knowing: we publish as com.greencalculus/api, a DNS namespace, and GitHub
OIDC only ever grants io.github.<org>/*. So the registry step signs with the key
matching the v=MCPv1 TXT record on greencalculus.com, held as MCP_PRIVATE_KEY.
scripts/rotate-registry-key.sh generates a
fresh pair and installs it without ever printing the private half; it prints the
TXT record to publish. Without the secret the registry step skips and says so —
npm still publishes.
Also available
REST API and docs — https://greencalculus.com/developers
Client SDKs (Python, JS/TS) — https://github.com/greencalculus/greencalculus-sdk
Official MCP registry —
com.greencalculus/api
Licence
MIT — see LICENSE. The licence covers this bridge. Emission-factor data returned by the API carries the licence of its underlying source, which is named in every response.
Available Tools
12 toolscalculate_activityA
Turn activity data into greenhouse-gas emissions: emissions = activity × factor. Give an amount + unit and a factor key; the unit engine converts to the factor basis (MWh→kWh, tonne→kg, gallon→litre, mile→km) and returns the emissions with the working, the GHG Protocol scope, and the source. Use search_factors / lookup_factor to find the factor key.
| Name | Required | Description | Default |
|---|---|---|---|
| activity | Yes | { "value": <number>, "unit": "<unit e.g. kWh, MWh, litres, tonne, km>" }. | |
| factor_key | Yes | Canonical emission-factor key. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses the unit conversion behavior (MWh→kWh, tonne→kg, gallon→litre, mile→km) and the output structure (emissions with working, GHG Protocol scope, source). This is transparent for a calculation tool with no side effects. It does not mention error handling or rate limits, but that is not critical here.
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 two sentences, front-loaded with the core purpose and formula. It packs essential details (unit conversions, output, factor lookup) without redundancy. Every sentence earns its place, and it is highly scannable.
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 simplicity (2 params, no output schema), the description fully covers what an agent needs: what it does, how to provide inputs, unit conversion logic, and what it returns. It also includes a prerequisite step (find factor key) and directs to appropriate tools. Without an output schema, it adequately explains return values.
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% (both parameters described), so baseline is 3. The description adds extra meaning by explaining the unit handling (converting to factor basis) and the output fields, which goes beyond just listing parameter names. It clarifies that activity is an object with value and unit, and factor_key is canonical, complementing 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 clearly states its purpose: converting activity data into greenhouse-gas emissions using the formula emissions = activity × factor. It also details the unit conversion and what is returned (working, scope, source), distinguishing it from generic tools. The mention of finding factor keys via search_factors/lookup_factor differentiates it from specific calculation tools like calculate_electricity or calculate_freight.
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 provides clear usage guidance: give an amount + unit and a factor key, and explicitly instructs to use search_factors or lookup_factor to find the key. It implies this is the generic activity calculator, but does not explicitly exclude specialized alternatives like calculate_electricity or calculate_freight. Still, the workflow is well-defined.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_business_travelA
Business travel emissions (Scope 3 Cat 6), distance method: emissions = km × passengers × factor. Air factors come in with_rf / without_rf (radiative forcing) variants. Find factors via search_factors (section "business_travel").
| Name | Required | Description | Default |
|---|---|---|---|
| distance | Yes | { "value": <number>, "unit": "km|mi" }. | |
| factor_key | Yes | Per-passenger-km travel factor key. | |
| passengers | No | Optional, defaults to 1. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must convey behavior. It mentions the formula, factor variants (with_rf/without_rf), and dependency on search_factors, but does not disclose output format, potential errors, or any side effects. It's a read-only calculation implied, but not stated, and edge cases like missing factors are not addressed.
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, each earning its place. The first sentence states purpose and formula; the second gives critical factor-context and lookup guidance. No filler or redundancy.
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?
For a calculation tool with full schema coverage, the description covers the core formula, factor sourcing, and scope. It lacks explicit output details, but given no output schema and that the result is an emissions estimate, the description is sufficiently complete for a competent agent.
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%, providing baseline 3. The description adds value by explaining factor_key variants (with_rf/without_rf) and directing users to search_factors for valid keys, which goes beyond schema basics. It also clarifies the distance unit combinations via the formula.
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's purpose: calculating business travel emissions (Scope 3 Cat 6) using the distance method, including the formula. It distinguishes itself from sibling tools by naming the specific category and method, making it unambiguous which tool to choose.
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 implies usage context by naming the distance method and pointing to search_factors for factor lookups, but it doesn't explicitly state when to avoid this tool or mention alternatives for other categories. It provides clear context but lacks explicit exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_electricityA
GHG Protocol Scope 2 for purchased electricity, both methods. Always returns location-based (grid-average) emissions; also returns market-based when you supply a contractual supplier_factor (e.g. a green tariff / REC = 0) or a market_factor_key (residual mix). Find grid keys via search_factors (section "grid").
| Name | Required | Description | Default |
|---|---|---|---|
| consumption | Yes | { "value": <number>, "unit": "kWh|MWh|GWh" }. | |
| supplier_factor | No | Optional contractual factor { value, unit } (wins over market_factor_key). | |
| market_factor_key | No | Optional: residual-mix / supplier grid factor key. | |
| location_factor_key | Yes | Grid-average factor key, e.g. grid.gbr.electricity.location_based. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It transparently discloses that location-based is always returned and market-based is conditional, and even gives an example (green tariff/REC=0). However, it doesn't explicitly state precedence behavior (supplier_factor wins over market_factor_key), which is only in the schema description.
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 three sentences, front-loaded with the core purpose, then covering behavior, alternatives, and a pointer to a related tool. Every sentence adds value with no redundancy or fluff.
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 has 4 parameters, no output schema, and no annotations; the description covers the purpose, behavior, and how to source factor keys. It lacks explicit details about output format, but that isn't required given the absence of an output schema. It adequately addresses the complexity of the tool.
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 adds meaningful context by explaining that location_factor_key is grid-average, market_factor_key is residual-mix, and supplier_factor can be a contractual value like a green tariff/REC=0. This goes beyond simply repeating parameter names.
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 calculates GHG Protocol Scope 2 for purchased electricity and explicitly identifies both methods (location-based and market-based). It distinguishes itself from sibling tools like calculate_activity and calculate_embodied by specifying the exact resource and metric.
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 gives explicit guidance on when market-based results are available (when supplier_factor or market_factor_key is supplied) and clarifies that location-based is always returned. It also directs users to search_factors for finding grid keys, providing a clear path to obtaining necessary inputs.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_embodiedA
Whole-life embodied carbon for materials, per EN 15978. Give a material key + quantity (+ optional boundary A1-A3 / A1-A4 / A1-A5 / A1-C); it assembles the declared lifecycle modules (A1-A3, B, C1-C4, D) into stages, totals the boundary, reports module D separately, and flags any missing stage as not-assessed (never zero). Find material keys via search_factors (section "materials").
| Name | Required | Description | Default |
|---|---|---|---|
| materials | Yes | Each: { material_key, quantity:{value,unit e.g. m3/kg/tonne/m2}, boundary? }. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden. It discloses key behavioral traits: assembles lifecycle modules, reports module D separately, and flags missing stages as 'not-assessed' (never zero). It does not mention side effects or authentication, but for a calculation tool these are likely negligible and the core behavior is well explained.
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 two sentences, front-loads the purpose, and packs necessary details (modules, boundary, missing-stage behavior, key lookup) without redundancy. Every sentence earns its place.
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?
For a single-parameter tool with a well-documented schema and no output schema, the description covers the behavior, output logic, and usage thoroughly. It explains what the tool does with inputs and its output conventions (e.g., module D separately, missing stages flagged), making it complete for an agent.
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 schema already describes the materials array structure fully (100% coverage), but the description adds the boundary options and directs the agent to search_factors for valid material keys—useful context beyond the schema. This meaningfully aids correct invocation.
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 calculates whole-life embodied carbon for materials per EN 15978, with specific details on module assembly and boundary handling. It implicitly distinguishes itself from siblings like calculate_pcaf by focusing on materials and using the EN standard.
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?
Provides concrete usage guidance: tells the agent to find material keys via search_factors, and lists optional boundary choices (A1-A3, A1-A4, etc.). It does not explicitly state when not to use this tool, but the material-specific framing and reference to search_factors give adequate context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_freightA
Freight & logistics emissions (Scope 3 Cat 4 & 9), GLEC tonne-km method: emissions = tonnes × km × factor. Find mode factors via search_factors (section "freight" or "freight_detailed"), e.g. freight.road_hgv.tonne_km.
| Name | Required | Description | Default |
|---|---|---|---|
| mass | Yes | { "value": <number>, "unit": "tonne|kg|lb" }. | |
| distance | Yes | { "value": <number>, "unit": "km|mi|nmi" }. | |
| factor_key | Yes | Per-tonne-km freight factor key. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the behavioral disclosure burden. It transparently reveals the calculation model (emissions = tonnes × km × factor), the GLEC methodology, and the dependency on factor_key lookup. It does not describe output units or error behavior, but the formula is the core behavioral trait for this calculator.
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 purpose, and no filler. The formula and factor-lookup guidance are packed efficiently into a compact description.
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 has no output schema and no annotations, so the description must cover both inputs and behavior. It explains the input semantics via the formula and points to the factor source, but it stops short of explicitly stating the output emission unit or result format. Overall, it is complete enough for a straightforward calculator tool.
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 the baseline is 3. The description adds value by showing how mass, distance, and factor combine in the formula and by giving a concrete factor_key example (freight.road_hgv.tonne_km), which clarifies the expected key format 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 specifies a clear verb and resource: calculate freight/logistics emissions using the GLEC tonne-km method. It also narrows scope to Scope 3 Categories 4 & 9, which distinguishes it from sibling calculators like calculate_activity and calculate_spend.
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 gives clear context for when to use this tool: freight & logistics emissions via tonne-km. It proactively directs users to search_factors for factor lookup with a concrete section and example, but it does not explicitly state when not to use this tool versus other calculate_* siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_pcafB
Compute PCAF Part A financed emissions for a portfolio. Returns each holding's attribution factor and financed emissions, the portfolio total, the outstanding-weighted data-quality score, and the audit trail (formula + PCAF source).
| Name | Required | Description | Default |
|---|---|---|---|
| holdings | Yes | Each: { outstanding_amount, denominator:{type:"evic"|"equity_plus_debt", value}, company_emissions:{value,unit?} OR estimate_from_spend:{amount_usd, sector_key}, data_quality_score? }. | |
| asset_class | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavior. It mentions outputs (attribution factors, data quality score, audit trail) but does not state if there are side effects, authentication needs, or limitations. It doesn't clarify whether it mutates data or just reads. Given no annotations, this is insufficient.
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 a single sentence that efficiently conveys the tool's purpose and outputs without unnecessary verbosity.
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 description provides context about PCAF Part A and outputs, but lacks details on prerequisites, when to use vs other PCAF tools, or any limitations. Given no annotations, it leaves some context to guesswork.
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 'holdings' parameter has a description outlining the structure (outstanding_amount, denominator, emissions or spend data), but the 'asset_class' parameter is undocumented. Schema coverage is only 50%, so some parameters lack clear semantics.
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 specifies the tool's verb ('Compute'), resource ('PCAF Part A financed emissions'), and output details (attribution factor, portfolio total, data-quality score, audit trail). It distinguishes from sibling tools like calculate_embodied or calculate_spend by focusing on the PCAF Part A standard.
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 implies use for PCAF Part A financed emissions calculation, but it doesn't explicitly state when to use this over alternative calculation tools (e.g., calculate_spend) or provide exclusion criteria. It gives some context but lacks explicit guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
calculate_spendA
Spend-based (EEIO) Scope 3 screening: emissions = spend × economic-intensity factor. Spend must be in the factor's own currency/year (no FX). Find sector factors via search_factors (section "spend_based"), e.g. spend_based.us.naics6.541511.custom_computer_programming_services.
| Name | Required | Description | Default |
|---|---|---|---|
| spend | Yes | { "value": <number>, "currency": "USD|GBP|EUR|SGD" }. | |
| factor_key | Yes | Spend-based (EEIO) sector factor key. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden. It mentions the input constraint (currency/year) but does not explicitly state whether the tool has side effects or read-only status. As a calculation, it's likely safe, but this is not confirmed.
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 concise, two sentences that pack the formula, the constraint, and a reference to search_factors. No unnecessary details, well-structured for quick comprehension.
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 there is no output schema, the description adequately explains the calculation context, including the EEIO methodology and how to obtain factor keys. The output (emissions) is implied by the formula, so it's sufficient.
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 schema provides basic descriptions, but the tool description adds significant meaning by explaining the spend format requirement and giving an example factor key. This enriches the understanding of both 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's purpose: calculating emissions using spend and economic-intensity factor, with the formula explicitly provided. This distinguishes it from sibling tools like calculate_activity or calculate_embodied.
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 explains the spend-based approach, emphasizes the currency/year constraint, and directs users to search_factors for finding factor keys. While it doesn't explicitly contrast with alternatives, the specific method and constraints make usage clear enough.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
explain_absenceA
Ask why a factor is NOT in the corpus. The reasoned counterpart to coverage: where a country reports zero rows for an inventory family, this says whether that is the world's limit or our backlog. Five classifications: "structural" (no publisher issues this anywhere — stop looking, and do not silently substitute another country), "not_yet_sourced" (a publisher exists and is named; it is our backlog), "refused" (we found it and declined — the reason is stated), "held_not_counted" (we DO hold it — see we_hold for the key), "coupled" (empty only because another family is empty). Each record names the publisher checked, the route tried, a confidence and a review date, and reports stale:true once past review. These are authored judgements about what the world publishes, not values derived from our data. Call this before concluding that a gap is permanent, and before telling a user to look elsewhere.
| Name | Required | Description | Default |
|---|---|---|---|
| family | No | Inventory family, e.g. "water", "wtt", "travel", "spend", "heat". | |
| country | No | ISO-3166 alpha-3 code, e.g. "can". | |
| classification | No | Filter: structural | not_yet_sourced | refused | held_not_counted | coupled. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description bears the full burden. It transparently discloses that results are 'authored judgements' not derived data, mentions the stale flag, and details the output fields (publisher, route, confidence, review date). This goes beyond surface-level description.
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 verbose, with several sentences repeating the same idea (e.g., 'reasoned counterpart to coverage' and 'authored judgements'). It could be tightened while preserving key details, unlike concise equivalents like the high-scoring example.
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?
Despite verbosity, it is thoroughly complete: explains the purpose, every classification, the output structure, the nature of the data (judgements vs. derived), and the appropriate timing for use. Nothing essential is 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?
The schema already covers all parameters with descriptions. The tool description adds depth to the 'classification' parameter by explaining each enum value in detail, but does not significantly enhance understanding of the other parameters. Baseline 3 is appropriate.
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's purpose: to explain why a factor is not in the corpus, with detailed classifications. It distinguishes itself by being the 'reasoned counterpart to coverage' and provides specific use cases, making it distinguishable from sibling tools like lookup_factor.
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 gives explicit guidance on when to use the tool ('Call this before concluding that a gap is permanent...'), but it does not explicitly name alternative tools or state when not to use it. The guidance is implied rather than directly contrasting with siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
lookup_factorA
Look up a single greenhouse-gas emission factor by its canonical key. Returns the value plus an audit envelope: provenance (publisher, exact source cell, retrieval date, LICENCE and whether it may be redistributed, with the attribution the licence requires) and verification (whether the per-gas components sum to the headline, the GWP set, and the source note stating what the publisher did NOT provide). If the key does not exist you get candidate keys back rather than a dead end. Use search_factors first if you do not know the key.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | Canonical factor key, e.g. "grid.gbr.electricity.location_based". |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden and does so thoroughly. It discloses what is returned (value plus audit envelope), details provenance and verification fields, and explains the missing-key fallback behavior with candidate keys.
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?
Three sentences, each earning its place: operation, return envelope details, and usage guidance. The most important information is front-loaded in the first sentence, and the detail is dense but not bloated.
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?
Despite no output schema and no annotations, the description is complete for a single-parameter lookup tool. It explains the return shape, provenance and verification details, error behavior, and when to use the sibling tool, leaving no critical ambiguity.
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% for the single 'key' parameter, including an example. The description reinforces that the lookup is by 'canonical key' but does not add substantial parameter semantics beyond the schema, so the baseline of 3 is appropriate.
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 uses a specific verb and resource: 'Look up a single greenhouse-gas emission factor by its canonical key.' It also distinguishes itself from siblings by explicitly directing users to search_factors when the key is unknown, and describes the narrow lookup scope versus broader search/calculation tools.
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?
Explicit guidance is provided: 'Use search_factors first if you do not know the key.' This clearly states when this tool is appropriate and names the alternative, which is exactly the kind of usage guidance expected.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
lookup_factorsA
Look up SEVERAL emission factors by key in one call, each with the same audit envelope lookup_factor returns — provenance (publisher, exact source cell, retrieval date, licence, redistribution) and verification. Use this instead of calling lookup_factor in a loop: a portfolio or a multi-country comparison is one call, not one per factor. Keys that do not exist come back in not_found rather than failing the batch.
| Name | Required | Description | Default |
|---|---|---|---|
| keys | Yes | Canonical factor keys, e.g. ["grid.gbr.electricity.location_based", "grid.fra.electricity.location_based"]. Maximum 25 per call. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description must carry behavioral disclosure. It does so well by describing the returned audit envelope (provenance, verification) and the non-failing not_found behavior. It stops short of discussing auth or rate limits, but those are not critical for this tool.
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?
Three focused sentences with no filler: first states what it does, second gives usage guidance, third clarifies error handling. The key behavior is front-loaded.
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 description covers purpose, batch behavior, return envelope, and error handling for missing keys. Combined with the schema's key example and max count, an agent has enough to call it correctly. It could additionally point to search_factors for finding valid keys, but that is a minor gap.
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%, and the parameter description already explains canonical keys, provides examples, and states the max of 25. The description adds context about batch semantics but does not need to expand parameter meaning further.
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?
Clearly states it looks up several emission factors by key in one call and returns the same audit envelope as lookup_factor. It is explicitly differentiated from the singular sibling lookup_factor.
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?
Directly instructs to use this tool instead of calling lookup_factor in a loop and describes the batch context, e.g., portfolio or multi-country comparison. This gives clear when-to-use guidance and names the alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
resolve_factorA
Find the best emission-factor key(s) for a plain-language description — the hardest step is picking the right key out of ~16,000. Returns ranked matches, each carrying the key, value, unit and a confidence score; feed the chosen key to a calculate_* tool or lookup_factor. Prefer this over guessing a key. PUT THE COUNTRY IN THE DESCRIPTION. Geography is read from the description text itself, not from a separate field — "diesel per litre" and "diesel per litre France" resolve differently, and omitting the country will quietly return a factor from somewhere else marked "geo_match":"proxy". ACT ON THE LABEL. Every candidate carries label: "accept" or "review", plus "why". "accept" means confidence >= 0.85 and no demotion applied — right about nine times in ten. "review" means the answer may be usable but something is off (low confidence, only one term matched, a proxy country, or a gate demoted it); confirm it before adopting the number rather than using it silently. Roughly half of CORRECT answers are also flagged "review" — that is the intended trade, so treat "review" as "check this", not "discard this". A MISS MAY EXPLAIN ITSELF. When nothing matches, or the only matches are from the wrong country, the response may carry an "absence" object saying WHY. classification "structural" means no publisher issues this anywhere — STOP, do not retry with reworded queries and do not substitute a different country without saying so. "not_yet_sourced" means a publisher exists and we have not ingested it (the publisher is named). "refused" means we found the data and declined it, with the reason. "coupled" means this reads empty only because a related family is empty. Use explain_absence to ask the same question directly.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Optional, default 5. | |
| section | No | Optional section filter, e.g. "fuels", "grid", "freight". | |
| description | Yes | What you need a factor for, INCLUDING the country if it matters, e.g. "UK grid electricity", "diesel per litre France", "hotel stay Japan". Geography is parsed from this string. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does so thoroughly: it explains that geography is parsed from the description, that omitting country yields a 'geo_match':'proxy' result, that 'review' is intentionally over-inclusive, and that absence responses have structural meanings that should stop the agent from retrying. This is far beyond minimal behavioral disclosure.
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 long but each paragraph earns its place: scoping, label semantics, and absence handling are all needed for correct invocation. The use of short capitalized hooks ('PUT THE COUNTRY IN THE DESCRIPTION', 'ACT ON THE LABEL', 'A MISS MAY EXPLAIN ITSELF') front-loads key behaviors and makes the density navigable.
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 three parameters, no annotations, and no output schema, the description provides everything needed to use the tool correctly: what it returns, how the main parameter behaves, how to interpret result labels, what absence responses mean, and how to hand off to related tools. No critical guidance appears 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?
Schema coverage is 100%, so baseline is 3, but the description adds real meaning beyond the schema for the critical 'description' parameter: it emphasizes the country must be embedded in the text and gives concrete examples ('diesel per litre France'). This extra semantic context justifies a 4 above baseline.
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 operation ('find the best emission-factor key(s)') and a concrete resource ('for a plain-language description'), and explains the tool's distinctive role against the 16,000-key problem. It also positions the output as ranked matches with key/value/unit/confidence, and routes the chosen key onward to calculate_* tools or lookup_factor, which separates it from 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?
The description gives explicit usage direction: 'Prefer this over guessing a key', tells the agent to feed the chosen key to calculate_* or lookup_factor, and points to explain_absence for querying absence directly. It also provides actionable when-to-use/when-not-to-use guidance through the 'accept'/'review' labels and the absence classifications.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
search_factorsA
Find emission factors by section, key prefix, or free text. Returns each match with its key, name, section, VALUE, unit and gas — enough to choose between them or read a few numbers without a second call. For one factor's full audit envelope (publisher, exact source cell, retrieval date, licence, verification) call lookup_factor; for several, call lookup_factors.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max results (default 20). | |
| query | No | Free-text search over factor names/keys. | |
| section | No | Restrict to a section, e.g. "grid", "fuels", "freight". | |
| key_prefix | No | Restrict to keys starting with this prefix. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of behavioral disclosure. It honestly describes the returned fields and clarifies that full audit details are intentionally deferred to lookup tools. It does not describe match semantics or empty-result/pagination behavior, so it is not quite a 5.
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?
Three dense sentences with no filler. The primary purpose is front-loaded, the return contract is summarized, and the routing guidance is placed at the end.
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 description is complete for this tool category: it covers what is searched, what is returned, what is omitted, and which sibling tools cover the omitted case. Since there is no output schema, explicitly naming the returned fields is valuable and sufficient.
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 all four parameters are already documented. The description echoes the search modes by mentioning section, key prefix, and free text, but it does not add any meaning 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 clear verb and resource: 'Find emission factors by section, key prefix, or free text.' It also lists the exact fields returned, which immediately differentiates it from lookup_factor and lookup_factors.
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 explicitly says when to switch to alternatives: 'for one factor's full audit envelope ... call lookup_factor; for several, call lookup_factors.' This gives the agent a concrete routing decision rather than leaving it to infer.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
1 tool update
v1.0.3- Added
lookup_factors
11 tool updates
v0.1.0- First observed
calculate_activity - First observed
calculate_business_travel - First observed
calculate_electricity - First observed
calculate_embodied - First observed
calculate_freight - First observed
calculate_pcaf - First observed
calculate_spend - First observed
explain_absence - First observed
lookup_factor - First observed
resolve_factor - First observed
search_factors
TDQS
Scored across 12 tools
The seven calculate_* tools map cleanly to distinct emissions categories, and the four factor-retrieval tools (search_factors, resolve_factor, lookup_factor, lookup_factors) are explicitly cross-referenced to guide selection. Still, search_factors and resolve_factor both 'find' factors, and lookup_factor vs lookup_factors differ only by cardinality, leaving some borderline overlap an agent must read carefully to avoid misselecting.
Every tool follows a predictable verb_noun snake_case pattern: search_factors, resolve_factor, lookup_factor(s), calculate_activity/embodied/pcaf/electricity/freight/spend/business_travel, explain_absence. No mixed conventions, so the naming is highly predictable.
Twelve tools is well-scoped for an emissions-factor and GHG-calculation server, with each calculate_* earning its place and the retrieval tools covering search, resolve, single, and batch lookup. Nothing feels padded or thin.
The surface covers the full workflow: find/verify/resolve factors, compute across multiple Scope 1-3 and lifecycle methods, and explain gaps via absence classification. Minor omissions exist (e.g. some Scope 3 categories like waste/water and any write/update capability), but core GHG accounting workflows reach no dead ends.
Maintenance
Related MCP Connectors
Sourced carbon emission factors + audit-traced calculations an AI can cite.
Verified CO2e for any transaction, activity, flight, shipment or CBAM import. 200+ countries.
Deterministic Scope 1/2/3 GHG inventories with bundled factors and audit hashes.
Natural-language queries over a verified emissions knowledge graph, plus standards validation
Related MCP Servers
- FlicenseNot gradedqualityAmaintenanceEnables carbon accounting by matching activities to emission factors via semantic search and AI ranking, supporting ELCD and ecoinvent databases.1401-
- FlicenseAqualityDmaintenanceEstimates the environmental footprint of your AI use — energy (kWh), miles driven, water used for cooling, and CO₂ — plus a prompt-efficiency score, working with any AI client by measuring token usage.9-
- AlicenseNot gradedqualityAmaintenanceDeterministic verification for AI-generated analysis. Reconciliation, consistency and Excel-integrity checks that stop the line when the numbers don't add up.1MIT
- AlicenseAqualityBmaintenanceEnables AI agents to query verified-emissions knowledge graphs in natural language and validate data against supported standards, with metered billing and optional verified identity.16824Apache 2.0