Twilio SendGrid

sendgrid-rest-v3restprimary

98% coverage

Offload Valuejudged · weight 15 · Oct 5, 2026

Email sending is a genuine external side effect an agent cannot perform via inference: SMTP delivery, deliverability infrastructure, IP warmup, domain authentication/DKIM, bounce and spam suppression lists, and email address validation. These involve proprietary reputation data and compliance (unsubscribe groups, enforced TLS) impossible to replicate with reasoning tokens. Much of the surface area is admin CRUD (templates, contacts, settings), which caps it slightly below the top.

• https://www.twilio.com/docs/sendgrid/api-reference

  The SendGrid v3 Web API provides a REST interface to send email at scale and ensure your application can handle high volumes.

• https://www.twilio.com/docs/sendgrid/api-reference

  The SendGrid v3 Web API provides a REST interface to send email at scale and ensure your application can handle high volumes.

• https://www.twilio.com/docs/sendgrid/api-reference

  The SendGrid v3 Web API provides a REST interface to send email at scale and ensure your application can handle high volumes.

Interaction Costmeasured · weight 15 · Oct 5, 2026

Median over 2 successful run(s): 10015 tokens, 2 calls. Ratio to the best in "transactional-email" (3 surfaces measured, v0.2 scale). Cold, without documentation: 1/1 succeeded.

Error Recoverabilityprobed · weight 15 · Oct 5, 2026

unknown_endpoint → HTTP 404, clarity 30/100 (field named: no, allowed values: no, RFC 9457: no) · wrong_type → HTTP 400, clarity 30/100 (field named: no, allowed values: no, RFC 9457: no) · hallucinated_enum → HTTP 400, clarity 50/100 (field named: no, allowed values: yes, RFC 9457: no) · unknown_field → HTTP 200, clarity 25/100 (field named: no, allowed values: no, RFC 9457: no) · missing_required_param → HTTP 400, clarity 60/100 (field named: no, allowed values: yes, RFC 9457: no) · idempotency_replay → HTTP 201, clarity 30/100 (field named: no, allowed values: no, RFC 9457: no)

• https://api.sendgrid.com/v3/templates

  HTTP 401: {"errors":[{"field":null,"message":"authorization required"}]}

• https://api.sendgrid.com/v3/templates/nonexistent_resource_xyz

  HTTP 404: {"error":"Resource not found"}

• https://api.sendgrid.com/v3/templates?page_size=not_a_number

  HTTP 400: {"error":"must be an integer"}

• https://api.sendgrid.com/v3/templates?generations=nonexistent_generation

  HTTP 400: {"error":"The generation you specified is invalid. Valid generation values include 'legacy' and 'dynamic'"}

Doc Legibilitymeasured · weight 12 · Oct 5, 2026

text/markup ratio 3.6% (weight 30) · rendering without JavaScript undetermined (excluded from the calculation) (weight 25) · machine-readable spec: none found (weight 25) · llms.txt: https://www.twilio.com/llms.txt (weight 10) · 0 runnable example(s) (weight 10). Weighted average over 75 points of available sub-criteria.

• https://www.twilio.com/docs/sendgrid/api-reference
• https://www.twilio.com/llms.txt

Auth Frictionmeasured · weight 10 · Oct 5, 2026

Authorization: Bearer <key>, verified by a successful call. One header, no ceremony.

• https://api.sendgrid.com/v3/templates

  HTTP 401: {"errors":[{"field":null,"message":"authorization required"}]}

• https://api.sendgrid.com/v3/templates/nonexistent_resource_xyz

  HTTP 404: {"error":"Resource not found"}

• https://api.sendgrid.com/v3/templates?page_size=not_a_number

  HTTP 400: {"error":"must be an integer"}

• https://api.sendgrid.com/v3/templates?generations=nonexistent_generation

  HTTP 400: {"error":"The generation you specified is invalid. Valid generation values include 'legacy' and 'dynamic'"}

Safety & Reversibilityprobed · weight 10 · Oct 5, 2026

Two identical POSTs with the same Idempotency-Key header created TWO distinct resources (d-05d889cf52d94f55b4f11bed57417c4a then d-b08c4a7b6cdd423390786de55677bb66). Every network timeout becomes a duplicate. (weight 35) · Isolated test environment available. (weight 25). Weighted average over 60 points of measured sub-criteria.

• https://api.sendgrid.com/v3/templates

  HTTP 401: {"errors":[{"field":null,"message":"authorization required"}]}

• https://api.sendgrid.com/v3/templates/nonexistent_resource_xyz

  HTTP 404: {"error":"Resource not found"}

• https://api.sendgrid.com/v3/templates?page_size=not_a_number

  HTTP 400: {"error":"must be an integer"}

• https://api.sendgrid.com/v3/templates?generations=nonexistent_generation

  HTTP 400: {"error":"The generation you specified is invalid. Valid generation values include 'legacy' and 'dynamic'"}

Payload Efficiencyprobed · weight 8 · Oct 5, 2026

No discoverable field selection (tested fields, select, _fields, expand, properties): the agent swallows the whole resource. (weight 35) · No cursor pagination marker in the response. (weight 20) · Nested envelope or non-list shape. (weight 10) · No ETag. (Compression is not measurable: the runtime decompresses it and strips the header.) (weight 10). Weighted average over 75 points of measured sub-criteria.

• https://api.sendgrid.com/v3/templates

  HTTP 401: {"errors":[{"field":null,"message":"authorization required"}]}

• https://api.sendgrid.com/v3/templates/nonexistent_resource_xyz

  HTTP 404: {"error":"Resource not found"}

• https://api.sendgrid.com/v3/templates?page_size=not_a_number

  HTTP 400: {"error":"must be an integer"}

• https://api.sendgrid.com/v3/templates?generations=nonexistent_generation

  HTTP 400: {"error":"The generation you specified is invalid. Valid generation values include 'legacy' and 'dynamic'"}

Task Atomicitymeasured · weight 6 · Oct 5, 2026

Median over 2 successful run(s): 10015 tokens, 2 calls. Ratio to the best in "transactional-email" (3 surfaces measured, v0.2 scale). Cold, without documentation: 1/1 succeeded.

Prior Knowledge Coveragemeasured · weight 5 · Oct 5, 2026

Median over 2 successful run(s): 10015 tokens, 2 calls. Ratio to the best in "transactional-email" (3 surfaces measured, v0.2 scale). Cold, without documentation: 1/1 succeeded.

Async Compatibilityprobed · weight 2 · Oct 5, 2026

POST /mail/send returns no trackable identifier: an agent can neither re-read nor wait for the result without a webhook. Long-polling / SSE not probed, excluded from the weighting.

• https://api.sendgrid.com/v3/templates

  HTTP 401: {"errors":[{"field":null,"message":"authorization required"}]}

• https://api.sendgrid.com/v3/templates/nonexistent_resource_xyz

  HTTP 404: {"error":"Resource not found"}

• https://api.sendgrid.com/v3/templates?page_size=not_a_number

  HTTP 400: {"error":"must be an integer"}

• https://api.sendgrid.com/v3/templates?generations=nonexistent_generation

  HTTP 400: {"error":"The generation you specified is invalid. Valid generation values include 'legacy' and 'dynamic'"}

Tool-Native (MCP)binary · weight 2

Does the vendor publish an official, maintained MCP server?